johnknoefler I loved that too. Mostly just the facts except for the guys dying folklore story. But even that was fast and clear. Usually I put these all on mute.
During the Vietnam war it was very common to build hardened aircraft shelters using the very same methods your using for your garage. The difference was the ends were left open some planes could taxi in one side and out the other. A rocket attack could land in front of a entrance and take out a plane. But shelters on either side would be untouched. A friend of mine built these shelters and he said they could absorb a 120 mm rocket attack without any issues. He also said they used slip forms for construction but other methods were also used.
Quonset hut reminds me of my basic training at USMRD San Diego during the Vietnam Era. The Quonset hut was hotter than hell and a heat magnet. Thanks, but no thanks, I would live in something else these days just because of the memories.
There is a House on Lake Tyler in Texas that was built in the 70's with this method. (North side of the lake near the center) They poured their foundation smoothed it out and then shoved rebar into the setting concrete foundation. After it set up they started adding rebar to the upright rebar and just started forming it over into dome shapes and tied it all together. They built windows by tying a hole in the side with rebar. Bolted a 2 x 4 block to the rebar at the bottom there they wanted the windows, then set a thick piece of tinted plexiglass over the hole openings. Leaving the paper covering on the plexiglass. Doors were framed the same way. Then they wrapped the entire 5 room structure in burlap and tied it to the rebar. All wirring was installed in conduit and switch boxes tied to the burlap and rebar. After shooting a lite coating of pool plaster against the burlap covered walls they waited fot it to set. Then went to town with the gunnite sprayer.The plexi winmdows were uncovered later in an oval shape. Since no windows, but the kitchen window over the sink opened to the outside and the house was so insulated and air tight, they had to install a dryer vent through the doors, just so they could close the doors. From the lake it looks ike a flying saucer at night when they have the outdoor lighting on. Was my wifes Uncles family that built it. Been inside it a few times when we went to the lake to go water skiing. He told me his air conditioner was just a small 3 ton unit, with a built in de humidifier in it, and his electric bill was almost nothing. Very nice and cozy inside. Lots of light but no heat through the windows. Like living in an Ice Chest!
I have been in the gunite- swimming pool business since college. I have four decades of experience with 7.5 sack gunite and wet shotcrete. The pictures show a fine job and the naysayers are simply wrong. Lack of knowledge is all over the web. Some folks should know what they talking about before they chime in!
I also been shotcreting pools fir 20+ years, they were just ok imo. Didn't get shit done dayv1 because they lacked experience in stacking the mud imo. It was OK, but I'm certain their is voids where the mud fell, the pladtic didn't do them any favors on being able to stack it up.
Nice concept. I once saw a documentary that showed how the nazis made so many hangars as fast as they did. They would put down a conveyor and make large mounds of pea gravel over them, lay rebar and concrete, then once hardened they would turn on the conveyors to remove or advance the gravel depending on if they were or were not going to continue adding length to the structure.
I saw one guy on the internet piled up a bunch of hay bales in the shape he wanted, covered it in concrete, and then tied a goat (or maybe it was a cow?) up to the open doorway. The goat cleared it out for him.
Now those boys (n gal) are not afraid of work. That is a lot of work ! Well done, Amazing. This vid should be shown in the Dept. of Human Services Admin (Welfare) waiting rooms.
Excellent, excellent, excellent. Simon, maybe showing the football team how to construct a house will help the growth of earth sheltered and bermed houses in future. Nothing wrong with thinking or building outside of the box (pun intended).
As you may already know ferro-cement construction should be applied monolithically. Many may not know or realize that ferro-cement construction was essential part of ship building during WWII. Thanks for the video.
If you are referring to the cold joints... This is not quite the same as ferro-cement, this is shotcrete. Google "shotcrete cold joints" to see how the way shotcrete is applied actually slams the molecules together and there is no cold joint. You can find lots of civil engineering papers on the subject, most of which involve a microscope to try and find the cold joint.
This isn't ferro-cement, this is shotctete. There is no such thing as a "cold joint" in shotcrete or gunite if properly cleaned and prepped. The individual pieces of sand/aggregate change shapes when shot and everything gets interlocked and filled in. Hard to explain without an illustration
@SimonHomeintheEarth u are absolutely correct, tge best way it was ever described to me was that tge individual pieces of sand and rock are shot at such a velocity that they will change shapes and everything gets locked in that way. Like shooting puzzle pieces that change their shape to fit in where it's shot, everything get interlocked
First off, GREAT video (really, the whole series). There's quite a few DIY videos that either give TOO much information, or not enough, or miss/mis-explain certain steps, etc. As I guy trying to learn about this particular type of project, your approach to the video-making is terrific. Thanks. One question, apologies if maybe you've addressed this somewhere else: Looking back on the project, do you know what the cost/time/efficiency differences there might have been if you'd have just made an ICF house throughout vs. using the Quonset hut? Thanks in advance.
Glad you like it. My favorite comment so far was that a viewer hated time lapse videos and, "could I just show the whole thing?" I said that would probably be a very long youtube video. ;^) She made the same comment on another video, so I said it wasn't time lapse, we just work really fast. ;^). But seriously though, for my own personal mental health, it does feel great after a long week(s) of what seems like slow progress to suddenly see it move so quickly in the time lapse. Even the most difficult and frustrating day suddenly seems so easy and productive. My wife is actually a little bit worried that someone out there may think it is easy and attempt something similar.
A couple of suggestions; It would be better to have finished one bay from start to finish in the spraying of concrete. Its not a good idea to have a cold joint in concrete as that is where it will break in any kind of seismic event. Also it will let in moisture and eventually the rebar will start to spaul out. In the future you might consider lightweight concrete if you have pumice in the area, I also would add in some fiber to that mix to get better confinement of the rebar. Finally I would use some "chairs" to support the rebar where it was touching the quonset hut. Rebar needs good coverage or it will just fail under load conditions and break out of the concrete. Probably at least a couple of inches of coverage. It looked to me like the ridge sagged from the first day to the second day of spraying on concrete. There was too much weight in the walls. It might have worked better if you had done one bay at a time and supported the inside while it cured. I didn't see any cylinders, but we require the taking of three or four cylinders of the concrete that are broken at 7, 14, and 28 days to make sure that the concrete has come up to the designed strength.
Shotcrete is not like regular concrete in that the way it is applied prevents cold joints... Google "Shotcrete cold joint" to see lots of engineering papers where they try to find cold-joints with a microscope after shooting on to old concrete. This is why it is used to repair bridges, etc. Also, if the concrete is getting wet, that means my waterproofing has failed and I will be having lots of other issues long before the rebar rusts. I plan to keep the concrete and rebar dry. Pumice is very expensive in my area and, since I want thermal mass and strength, I preferred high strength concrete to light weight concrete anyway. I did add glass fibers in the mix truck though. The shotcrete guy didn't care for it, and complained a bit and said it wouldn't really prevent cracking, but I added a few lbs per yard anyway. It was cool because you just toss the whole bag in because the bag its self is made of glass fibers. We did use hundreds of 1.75 inch rebar chairs to keep the lath away from the rebar and ensure coverage. If you can't see them in the video, just follow the link to the website for detail photos. Not sure what you mean about the sag, but it isn't noticeable in the final structure. There is some quilting between the rebar, but the stucco layer will smooth that out. We had to do it all at once. It would cost far too much to have them come out for each vault. In fact, I have already broken up the job more than I would have liked. I didn't support the inside because it didn't need support and that would have just been extra work and cost. We got plenty of concrete "samples" each day, even if we didn't keep the proper slump tests. Those were very strong and kept a nice sharp edge when we broke them up with a jackhammer. It was rated at something like 8500psi concrete.
8500psi is very strong concrete. My experience with structural shotcrete was doing seismic mitigation work for a school district in Southern California. We filled in classroom windows and thus formed "shear panels" which transfer energy from high in the building to the ground during an earthquake. There were typically 2 or 3 bays per classroom and we would fill in one from column to column. The roofs were concrete slabs and we experimented with building forms, cutting holes in the roof and pumping the concrete into the space. Of course that was after we epoxied in rebar grids to the existing members. Eventually the structural engineer allowed shotcrete, but cold joints were not allowed. Existing concrete has to be wetted down to prevent it sucking the moisture out of the new shotcrete before it is applied. If it dehydrates the shotcrete too fast it will mess up the curing and the strength. We also used an epoxy in some situations to bond the shotcrete to the existing concrete, but generally we relied on the rebar for transference of energy. One of the interesting things about that type of mitigation work is that you create a stronger part of the building and that is where the damage will occur during the next earthquake. The stiffer part of a building will resist the transfer of energy and that is where the cracking will occur. But the stronger building will also buy some time for the kids to get out, or at least that is the hope. Seriously the building looked more egg shaped after you started applying shotcrete in the video, but it have been an optical illusion.
Oh, I thought you were talking about a different video (the bedroom shotcrete). That one used hundreds of rebar chairs. This one only needed about a few dozen rebar chairs to keep the rebar off the steel Quonset. The Quonset did squish quite a bit just walking on it (point load), but because we shotcreted the sides first, the "squish" due to the concrete weight was less than just when a person walked around up there, so I wasn't too worried about it.
Foamcrete would be lighter, but weight isn't a concern. It is only cheaper if you can find someone setup to do it for a lower price. In my area, the lightcrete guys quoted me about 3 times the price. If I had that sort of extra money, I would have used it to spray foam over the outside of the strong shotcrete.
It didn't collapse. If I was really concerned that it had a significant chance of collapsing, I wouldn't have done it. ;) Or I would have done it with a thinner layer of concrete and then done it again a second time with the previous concrete supporting the weight of the second application.
@@joshblick Given that it's a perfect semicircle the forces almost completely cancel eachother out. Giant concrete sewage pipes are an example. They can hold hundreds of PSI of pressure.
@@00000005547 Semi-circles are not impervious to infinite pressures. Everything has "weight" and gravity does exist. And "giant concrete sewer pipes" are made in forms, not sprayed on a roof. We're not talking about cured concrete, we're talking about the weight of wet concrete.
Not too many earth sheltered homes out on the bayou. Usually, they are more popular in dry or sandy environments... But if you take the proper precautions, I guess you can do it anywhere.
An example of the kind of house never to build! Very labor intensive and how are you going to ever sell it to anyone else? This is the first video in a series but I have yet to see how you are going to comply with basic codes such as light and ventilation, insulation and engineering using shotcrete to structurally support the weight of earthen cover.
I complied with all building codes (and exceeded them). We have a very active building inspection department. Yes, it was labor intensive, as are many good things in life. Only people interested in a unique, durable and energy efficient home would be interested in buying it. There are many such people in the world, but especially in my county. However I can only sell it once, so I only need one of them to make an offer (when I am ready to sell).
I love this idea but is there any insulation on the OUTSIDE of the Quonset hut or on top of the concrete before you bury it ? How much condensation are you having inside the structure ?
Yes, I filled the valleys with 4 inches and then added 6 inches over the outside after the concrete, so R40? Plus the dirt and concrete... But yes, in the early summer, when the walls are cold but the outside air is hot and humid, condensation definitely happens. The steel is galvanized, so it doesn't seem to be causing any rust, but condensation does run down.
Former Landscape Architect....just like building a Gunite Swimming Pool just upside down... I have long been a proponent of Earth Integrated Architecture...
Very informative! Did you consider spray polyurethane foam exterior rather than concrete, they have it in different densities and a lot easier to spray?
Yes, I wanted to do that. It would have been a lot nicer. However, the cost was much higher. Sprayfoam in my area, capable of being used in this application, costs about 4 to 6 times the price of quality Foamular 250 rigid insulation and a heck of a lot more than the few little sheets of cheap polystyrene that I used here.
Oh, I see, I thought he meant spray foam over the steel and then add the concrete... If Russell meant instead of concrete, while then I really wanted this thing to be much stronger than spray foam... Although he does have a point. I know of a number of these quonset huts that were buried without the concrete.
The shotcreted steel arch building could likely survive a firestorm. The earth is nice extra insulation but what he effectively built was a small "hardened aircraft shelter" (HAS). By comparison foam would be easily melted and could be heated sufficient to burn. Concrete was the superior choice.
interesting. But I wondered about the shotcrete going on in stages with time gaps rather than in one continuous slower shoot. Won''t the patchy application leave weakened joints and lamination layers.
You can look up studies on "Shotcrete cold joints" to learn more. Basically, the studies apply shotcrete layers years or decades apart (after cleaning the first surface) and then cut a slice and examine the joints with a microscope. Because of the way that shotcrete applies the molecules, they bond on a molecular level and (if done correctly) there is no cold joint. This is why it is used to repair old crumbling bridges, etc.
I read all 250 comments on this video and haven't seen this addressed: My research into these Quonset kits is the ribs created by the manufacturer's equipment bend the steel to create a total profile dimension of a nominal 7" (depending on the diameter of the structure). You mentioned some 4" foam pieces (looks to be the white expanded stuff) in the top sections to save concrete and weight, but why did you not do this for the entire arch? I also see somewhere you mentioned 6" of concrete, yet don't explain where that thickness is. If it is 6" in the thinnest parts (crown of each rib), then that would be 13" in the gully of the ribs (thickest) where there is no foam. Due to the type of loading for the finished structure, wouldn't a single thickness of 6" throughout be sufficient? Or put a simpler way, if you had used an air inflated form, what thickness would the concrete be?
Yes, I wanted some insulation on the top of the quonset to lower the weight there (I was concerned about the wet weight). It also added some insulation against heat loss where I knew my earth would be thickest. On the sides of the quonset, I wanted lots of concrete for strength and I wanted a better thermal connection with the deep earth, so no need for insulation there. The 6 inches (roughly) was over the top of quonset, over the thinnest part. In the deep parts, you could add 7 inches and get to 13 inches, on the sides, they probably got several inches thicker than that. Yes, a single thickness of 6 inches would have been sufficient. Even 1 inch would be sufficient if placed correctly (I know of larger underground houses than mine that are only one inch thick), but the engineer was concerned about the skill of the shotcrete crew and wanted 6 inches to be safe. I agree that it would have been overly optimistic to expect the crew to follow the shape of the quonset precisely to give a uniform thickness. Much of how these things turn out is a series of compromises. But concrete is relatively cheap (~$100 per cubic yard that can cover 81 sqft at 6 inches thick) compared to the labor to place it in a fancy way. Concrete is even cheaper than the insulation per inch. If money was not a concern and labor was fully available, I would have liked to use spray foam to completely cover and protect the building and then shot six inches (or more) of concrete over that.
@@SimonHomeintheEarth Thanks for the response, I am planning on doing a 40' underground arch building using a Quonset as a form and you were the first I have seen do one below grade. Mine is in neighboring Lenawee County and I hoped to start it this year, but I'm getting a late start for the season. Will also build a round 2-story underground house (we think similarly independently) the following year (hopefully): th-cam.com/video/2LcGbi8_yoA/w-d-xo.html
What if you use this for a bridge? Over a river. Like the river would run through the opening. Cover in rebar mesh, then spray concrete. Perhaps, a thicker layer of concrete would be needed.
Thing is, you wouldn't need as many sections as you need for making a shelter. That's if you're making a bridge for a farm, a small bridge. 10 feet wide. I'm still researching this... So far cement bases on each side of the river, connected by H beams made of steel, covered by more steel, and a layer of reinforced concrete, seems to be, not the cheapest, but the best bang for your buck.
Yes, pretty confident it would work. Span matters a lot though. If the span is wide, you need to be more concerned with different materials expanding and contracting with temp variation... A cheaper way (and you can find lots of youtube videos for this) would be to just use a wood form instead of the Quonset hut. Then you just rip it out after the concrete setsand don't need to worry about the steel expansion or rust, etc.
You're the only one I can find placing shotcrete on the outside of one of these. Did you consult with the manufacturer about it? And where did you learn about the shot create? Thanks
Yes, and the company told me very clearly that they were not engineered to be buried, and then someone at the company sent me a separate email with pictures of a bunch of their Quonsets that people had buried anyway. However, they were all "direct" burial examples. I was just using the quonset as fancy formwork. It was far more than strong enough to carry the concrete load while the concrete set. Now it isn't under any significant load and the concrete is taking the earth load. When we shot the quonset, it deformed less than when we had someone (a point load) walking on it. I forget where I learned about shotcrete. I had read a lot of books (pre TH-cam). I did also need to have the structure officially engineered in order to get the building permit in my area.
Faster, cheaper, better insulated & stronger to just spray a monolithic dome in that shape. Also, drop the steel rebar and use basalt rebar. MUCH better.
Hey Patrick, Where is your data or what is your experience with alternatives? Putting up a Quonset hut was pretty fast (2 Fridays and two Saturdays by amateurs). The rebar was another couple Saturdays and none of the people involved had ever touched rebar before this project. Shotcrete was two more days (by pros who told me they would not take any job that required shooting from the inside as with a monolithic dome). You ever heard of a monolithic dome going up in that few amateur man hours? Cheaper? The structural part of this (footings, Quonset steel, rebar and shotcrete) cost maybe 17$/square foot. How much for a monolithic dome? Better insulated? That is an independent issue since I could put the same spray foam as would be used in a monolithic dome on the inside of my quonset, but I chose not to because it costs a lot more (and would make the inside ugly). Instead, I put 4 to 8 inches of Rigid insulation (R20 to R40) and at least 3 ft of earth over mine. I'll bet that is better than the average monolithic dome, traps more thermal mass and costs less. Stronger? I doubt it, but I am open to discussion. It would depend on things like the thickness and formulation of concrete, rebar layout, etc. The shape also matters, but only if the loading around it is optimal to that shape (as it is for my buried quonset). People who talk about how strong an egg shape is often forget that eggs are also very easily cracked open. As for steel rebar vs Basalt... I have used both on this project and each has their own advantages. In my area, Basalt costs nearly 30% more per length (assuming I use 3/16ths basalt to compare with half inch rebar). It is great in terms of ease of moving it or curving it, but it has very little structural stiffness. This makes it great for following the curve of an air form or against the dirt in a gunite pool, but pretty useless for the sort of 3D flying concrete I do on most of my construction. Finally... Choice. A monolithic dome wasn't want I wanted (architecturally), if you want one, then you build one. It was also the only building type prohibited in my area because neighbors think it is ugly.
Hempcrete is a fun idea, but it is not nearly as good as the proponents say it is. It is less than 1/10th the strength of concrete, so it can only be used as a fill wall. You usually see post and beam structure to carry the loads and then just unistructural hempcrete to fill the spaces between the structure. It is also difficult to find a supplier. I wanted to experiment with it a little, but, even in my rather liberal area where every 2nd billboard is for an mj shop and they even advertise cdb oil for pets, I couldn't find a supplier who could sell me the hemp, either mixed as hempcrete or on its own.
Hello. I am curious if a quonset hut can be nested inside of a larger quonset hut, with concrete of some type between the two? If the huts had sufficient thickness metal, would they be able to act as the rebar for the crete? Just thinking out loud, have no engineering degree or anything. What do you think? I see the actual hut seems to be the least expense of this style of building, so ... Thanks. Grey
I don't think you need the outer Quonset hut (and it would probably be very difficult to add). Also the Quonset in this case was $7K, the rebar was $2K, so the rebar would be cheaper than the outer layer of Quonset... Or, depending on your need, you could just use the Quonset and skip on the rebar. Even for buried Quonset huts, Most don't use concrete, they just bury the steel directly, but then you need to get the thicker steel for the Quonset, so that raises your price a bit.
I see. I was thinking the rebar plus labor would be more than the quonset. Thanks for your reply, Simon. I will look at more of your vids to see more of this project. Take care, Grey
The labor for putting up the single quonset was also much greater than the labor for the rebar. I would assume that putting up a second quonset (before or after the concrete between) would be considerably more difficult. Not sure how you would reach to tighten the bolts.
I was thinking more along the lines of using the two sizes as the form for the concrete. Either slide the larger over the smaller (on rollers) after they were constructed and fill with crete from the top through pre-cut fill holes, or pre-casting sections much like you made your arches, only using sections of the quonset huts as the form. Using this method would also entail some sort of large jig and need a way to lock the pieces together once erected. Just some thoughts, not defending them as better or even plausible, but I wanted to explain what I was thinking. Thanks, Simon. Grey
Yup, all sounds much more difficult than just using rebar to me... Although the precast arches idea sounds interesting, you would still need the rebar inside. From an engineering perspective, the rebar gives the concrete tensile strength because loads are transferred to the steel before the concrete can deform enough to crack. The rebar is rough to improve its connection with the concrete. I don't think the concrete would be very able to transfer its tensile loads to the smooth Quonset hut steel and would probably just separate from it instead. I suppose maybe you could "rough up" the quonset hut, but then you would risk ruining the galvanizing (and the quonset would rust) and that also sounds more difficult than just using rebar.
Yeah but they would have taken 5 years to build , 12,000 dollars in payoffs and bribes and the union would have sued even though they dont do that kind of work or want to , at the end it would cost 1,297,065 dollars and housed refugees .
I noticed in the time lapse, the forks on the front loader were going down. Are the seals going bad? I operated an old Case 570 backhoe with bad seals on the boom. It dripped so bad, I took several gallons of hydraulic fluid to fill it.
Yes, it goes down very slowly after I turn it off. The problem is better now then it was when the video was made. I opened up the front and found one of the cylinders between the front pedals was leaking just a tiny bit. Tightening the connection was enough to solve that problem. I have not found any other leaks and the hydraulic fluid levels have not gone down in the year since. I figure maybe the leak is just back thru the hydraulic pump? Anyway, I don't have time to deal with that problem and prefer to think of it as the "skid steer is putting its self away".
I love it! Thanks for sharing your project. I do wonder about what the square footage of the finished structure underground will be? Also what is the projected costing, especially compared to conventional construction? I do wonder if you're aware how this might hold up in even colder climates further north (I'm in Canada)? By the way, I'm saddened and embarrassed for you having to entertain so many stupid comments along with some very great ones.
Yea, the trolls are on the internet. Actually, I am Canadian, but living in Michigan now. As for this sort of construction, it is actually very affordable. You pay more for foundation, etc. but concrete is cheaper than wood and I won't need to put siding or brick on the outside. I am sure my home will cost less per square ft than my neighbors, but I do help with a lot of sweat equity. As for this type of construction in canada, look up Bill Lishman, the Canadian inventor/artist and Father Goose guy that they made the movie about. He lives in a house like this that is so unusual they didn't even try to replicate it for the movie. This is in Ontario somewhere. goo.gl/iWgRcC
Thanks for the update...coincidentally I live within a short drive of the Lishman House which the family has placed on local home tours for public view, I'll have to join the next one. Good luck with the rest of your project and keep us in the loop with more videos.
Nope, no problems with the Quonset hut. The only issue is that its wall are cool, so when you let in hot humid summer air, the quonset cools them off and water condenses on the inside. This makes the floor by the walls a bit damp on hot and humid days. This could be prevented by not letting in so much humid air... Or by letting it in more so that the walls warm up to ambient temps more quickly.
Nope. Two main reasons why. First off, I wanted a good thermal connection with the earth. If you insulate the structure too well, you lose that earth moderating effect. I did put insulation in the crenelations (so half insulated with 8 inches), but that was more to reduce the concrete weight and still left half the surface area open for heat exchange. Secondly, the cost of spray foam is pretty extreme, especially if you mean the kind that can support the weight of wet concrete without crushing. I priced it out (just out of curiosity) and it would have been the most expensive line item in the build by a wide margin. More expensive than the steel. More expensive than the concrete. And it would have hurt thermal performance... No thanks.
Offering monolithic concrete homes in Florida same design but will create a foam shell to shoot against from inside eliminating the steel building good luck nice solid home and like the faugh front might need to steal it.
Yea, on other parts of the build, I wanted to shoot from underneath against a form, but I couldn't find a single crew in my tri-state area that was willing to shoot from underneath. It is messy work and no one wanted to do it. I did consider importing a crew from down south, but couldn't afford it.
The OSB was just temporary, I have already removed it. It was fine under the concrete. I had put the shiny side out and I think it does have some sort of mildly waterproof coating built right in. Actually, some of the boards even had some sort of shiny plastic foil on one side.
I would love to have it all closed in by the end of 2017, but it is tough to plan that far away because each new phase has a learning curve and ends up taking longer than I thought it would. Instead, I try to plan smaller steps. For instance, I am fairly confident that we can get the next phase of shotcrete up before the end of May, which would mean we may be able to have the house 2/3rds buried before the end of April. But then I start on the rebar for the radial vaults on the center third, and that is a whole new ball game, so it is hard to predict how long before I could shotcrete that, etc.
Nope, we didn't reinforce it at all. Officially, it has a snow load capacity of 75 lbs per sqft, but the engineer's were not able to clearly tell me what that really meant. They just kept saying "75 lbs per square ft... Seventy - five - pounds - per - square - ft... but they couldn't tell me if the load was always vertical, if it could handle load just along the top without the sides also being supported, etc. Anyway, I knew of some others that had put even more load on theirs, so I just went for it. If we had started by applying the concrete to the top of this thing, then the building would have had to take the full weight of it and I am not sure how well that would have worked out. But we actually put the shotcrete on the footing, so the weight wasn't nearly as much on the building its self. So the first 6 ft have no load on the building... Then after that, it forms an arch, which carries most of the load. The building was just fancy formwork. Shotcrete sets up very quickly, and once self supporting, we could have removed (it would require magic) the quonset and the concrete would have stayed up anyway (without requiring magic).
Costs ended up (at the end of it when we moved in well past this point in the video) at about $92 per square ft. I didn't spray foam first because the kind of high psi foam that you can use in that application is considerably more expensive (6x) than sheets of XPS... I would have done it that way if the cost were closer.
Yea, one of those would really spice up my videos. I have a couple friends with decent drones but have not managed to rope them into filming something for me.
Welding rebar is a bad practice as it affects the tensile strength and will create a weak point of failure. Here in PA PENNDot specifically required wire tying only.
I think I commented on a similar comment elsewhere. Yes, welding can change the material properties of the steel, reducing ductility especially, but if you check the rules (probably also in PA), they actually have a lot of exceptions. For instance, you can "preheat" your welds, etc. In my case, I didn't need to pre-heat (those rules kick in for thicker rebar), also, I was using low Carbon rebar (it is stamped with a "w" on it, meaning, it is safe for welding. Also, in my structure, all the concrete is in compression all the time. By using vaults and arches, the house was designed without any concrete in significant tension. The inpector reviewed my situation and green lighted welding. It really helps a lot because we are climbing all over it (welded rebar is safer), but also because the shotcrete can't vibrate the welded rebar and cause other problems (such as voids).
Wiring is "safer" in terms of leaving the ductility, etc. of the rebar so that it won't fail under extreme flexing or tension... However, my design shouldn't have either of those, especially not on the skylight rebar where the primary reason for the rebar is just for holding up the shotcrete. I didn't weld any of the other garage rebar. I did weld rebar in other areas of the build (such as the bedroom vaults), even though it took extra time, because I was more concerned about the stiffness of the assembly with my crew and the shotcrete guys climbing all over it (actual "safety"). Also, with the formwork tied to the shotcrete, the impact frequency can cause tied rebar to shake quite a bit more. If the shaking doesn't cause the shotcrete to bounce right off, it can still leave internal voids... And those would be worse structurally (both compression and tension) then the welding. Again, this was not a problem on the garage where the formwork was the quonset hut and would not vibrate the rebar. These are all tradeoffs.
It's still standard to build newer generation HAS that way. The interior steel spall liner is much heavier than the Steelmaster building (it is NOT a Quonset hut, that has specific meaning and none of that now-obsolete framed style building are in production today) but the principle is the same.
Yes, someone from the company (unofficially) sent me a number of pictures of quonset huts that were burried directly without any concrete... But those were the much heavier grade quonsets. I was using the 22 gauge one. I think it was rated for a 75lb snow load.
I am still surprised that the rebar in the US and Brittany is placed in single bars? Why not using rebar netting much faster to work with an more support!?
You can buy welded wire mesh (WWR) on 6 inch spacing. I had used that for the slab reinforcement, but it would be insufficient for this. That rebar is about 1/8th of an inch thick and the sheets still get heavy and awkward. I can't imagine how I could move a net of rebar made of half inch thick steel bars... I literally put in 4,000 lbs of rebar on this building. Even if I could get a net that would be spaced according to the engineers specifications, and even if it only covered a quarter of the building per net, that would still mean trying to position 1000 lb rebar nets... And curve them at the same time? I was not equipped for that. Sometimes it is just easier to put the rebar in one piece at a time. Are you talking about thin little welded wire nets or do you actually use nets of half inch rebar in your area?
Back to the original comment on this thread... I can see the convenience of using WWR (welded wire reinforcement) as it is called here in the USA, but to be clear, smooth 1/8th inch thick wire, spaced every six inches is not stronger (does not provide more support) than half inch rebar spaced 1 ft apart. Its not even close. Also, the reinforcement of the concrete on this Quonset hut has a huge factor of safety more than the strength required to hold up the expected loads (both static and dynamic).
I'm thinking about doing this Simon .how much can I expect to pay ? I'm thinking of 40×30×16 ball park would be great.and I think this would make it hurricane proof .
I think I wrote the break down several times in the comments. In the end, it was something like ~$30 per square ft. The steel Quonset was only $7000, delivered. Concrete flatwork was 3$/sqft, plus the cost of concrete, etc.
Thanks Simon ..one more question..I was going to sink both sides of the hut into the concrete slab..instead of the track system they offer what do you think.and thanks again..mine will be near the coast,. I have calculated what I think is on the high side 40000 plus my lot.
@@o9rgeronimo979 Missed this one a year ago... How did your project go? For anyone else that sees this... You want to build on some solid concrete, not build the Quonset hut and then pour the slab around it. I thought the track system was too expensive, so I did the concrete groove trick and then grouted it in. Videos of that are all on TH-cam.
I'll answer three ways... If you mean this portion of the build (Quonset covered in concrete and buried), it was very cheap. With the steel, electrical, a small bathroom, doors, windows, rebar, concrete, etc. It cost less than 30$ per square foot to build. A regular house costs about 250$/sqft. If you mean the entire project, portions of which are rebar cages with shotcrete, etc. then we are in the ninety something range, but we are building it ourselves, so not fair to compare with costs that include all the labor. If you mean an earth sheltered home, built by hired workers, then companies like "formworks" or "terradome" claim those cost about 3% more than an equivalent above ground home. Of course, that extra cost is quickly saved in reduced heating and cooling.
is it asking too much to look at engineering specs for your burried Quonset hut section? Everyone I talk to here in New York tells me it can't be done. I show them your video and they say your structure won't last. I've been following your progress for years and it's the most amazing thing. I have a Quonset hut on its way now and I'm looking to mimic what you've done So that I can Have a big enough space to work in the winter without spending a fortune on heat.
Why wouldn't it last? Once the concrete is on there, the quonset isn't even taking any load. It could rust away to dust and I'd still have a thick reinforced concrete structure. But sure, email me or facebook me and I'll get you that page of the engineering plans. It is pretty basic. Just some rebar spacing. What gauge is your quonset?
@@SimonHomeintheEarth Thanks for getting back to me! I couldn't agree more. The steel is pointless after the concrete dries. NYS and especially my township, are completely devoid of imagination. If they've never seen it before, it can't be real. What email address should I use for you? the quonset is 18 gauge.
My Quonset is thinner than that. I think 20 or 22 gauge. Actually there is another guy on here (ForbiddTV) that plans to build one this summer. He plans to shoot over a Quonset hut built in reverse (overlaps and bolts backward) so he can take it apart from the inside and reuse it as formwork over and over again. He has a TH-cam channel and I am looking forward to seeing how that works out.
I think I mentioned it in the video, but it was about 2 tons of rebar over the outside of the quonset hut. (not including the walls or floor). I pay about 1000$ per ton, delivered.
reason I said above lived N Bend Or. when fire blazed thru town N 80s causing many homes 2 burn up I was woodland FF & taught wife & kids 2 git & house down everything yard home fence etc. thkfully fire stopped 1 block fm Us when wind shifted. I was outa state fighting roundtop fire N montana !
Yea, you'd think the insurance company would give me a break since the place is pretty much disaster-proof, but nope. They just smile and take my money. ;)
Why wouldn't you want to apply the concrete directly to the steel and have it bond? You could probably have even welded studs to the steel for extra bond.
Because of corrosion. The bond would be great at first, but eventually, I would expect to see corrosion coming thru the inside. Concrete holds moisture, leaks salts, etc. Not good for steel. It was just safer to keep the concrete off the steel. The shape of the concrete matches the steel and it is very thick and heavy, so I don't expect it to fall off anytime soon anyway.
I don't actually know anyone else who has done it the way I did it, but I have seen pics of directly buried Quonset huts (without the shotcrete) and I have heard stories of others covering them in concrete. But nothing "concrete" enough for me to give you a link to a specific instance. The Quonset hut vendors told me that it is not engineered for burial and that what I planned to do would void my warranty.
Sorry, I guess once a video has too many comments, TH-cam just stops telling me about new ones. But in answer to this question... It is quite nice inside. Yes, you could live there (just not at my place ;) , get your own). The only moisture problem is when I open up all the garage doors and let in the humid air in early summer. The quonset walls are still relatively cool compared to the hot humid air, at least they are below the dew point, and moisture condenses and runs down. The walls are galvanized, so it's not causing any real problem, but it does happen. Keeping the doors closed on hot humid days and letting in air via an earth tube instead will solve the problem. The rest of the year is fine. In winter, the walls are much warmer than the incoming air and in late summer/fall, they are warmer than the dew point.
Quonset hut is 30 wide by 40 long. 20 gauge steel. Shotcrete thickness varies because the crenelations are 7 inches deep, but the thinnest is 4 inches thick. Probably well over a ft thick at the base. Also 2 tons of rebar.
The engineer specified this rebar layout. He did also specify WWR with six-inch spacing for the floors, along with rebar. Maybe he just didn't think it was necessary here?
Yes, it did yellow a bit and got a little powder on it. I am sure not much R value was lost, but I was happy to get it all covered in stucco. That would be another video, but we don't have much stucco footage.
Is the net made up of half inch rebar (as specified by the engineer) or are you talking about WWR (welded wire reinformcement) that is light enough to lift but would not meet the engineer's requirements? I really doubt that a net of sufficiently thick rebar could be moved at all, let alone save me any time.
i have worked with concrete and i builded "Premade" housing structures. we used less than half inch and the buildings where 5 stories high. we used 2 nets and a large "Frame" with 16 mm re bars and tied them with the nets. and also if two person cant handle the nets. just connect it to the skylift and drag it on to the roof. pies of cake. www.armeringdirekt.se/armeringsnat/armeringsnat-12150?gclid=Cj0KCQiAyZLSBRDpARIsAH66VQISPR6Ta8vZdpL1teO8Fj5js8TrGDDh4NCWGGtpcrV09b1u9_LB9wcaAqTNEALw_wcB
I can imagine situations where using a 20ft long and 300lb net of rebar would be easier than tying your own. For instance, in a factory creating pre-fab panels, but I doubt it would have saved us anytime. All the rebar on this building (2 tons of it) went up in two Saturdays. I would have still needed many of these nets (at least 16 by my calculations) and they would have needed to be positioned and tied together... Nope. A few amateurs with simple rebar and tie wires just seems easier.
I did look into aircrete, It is not really structurally strong enough for burial as I plan for my earth-sheltered house, but it would have been a great way to create long-lasting insulating fill, especially to fill the voids between the vaults. However... 1) the only company in my region capable of producing enough at once (lightcrete systems inc) quoted me a ridiculous number. I could have bought all the equipment and started my own company for that much. They were so rude I actually considered doing that just so I could put them out of business. 2) I looked into buying the industrial scale equipment from California, but ended up deciding against it because it would still have been more expensive than using structural concrete (which is much much stronger) and putting 6 inches of rigid xps over it or even just filling all the voids with EPS and putting a thin cap of regular concrete over it. You can make your own rig and use a bottle of Dawn if you are mixing a bucket at a time, but I am doing a concrete truck every hour, so I needed something more industrial scale. 3) I wanted the concrete to have thermal mass and to be able to quickly absorb and transfer heat back and forth with the air inside and the earth under the umbrella outside, so aircrete really wouldn't have been good for that.
In ADDITION to the rebar, yes. Some, but not all, the shotcrete had fiberglass in it. I asked, but my supplier didn't carry the basalt fibers. Those fibers will hold small cracks a bit tighter but are not considered a substitute for rebar in substantial concrete structures like this.
Gunnite and shotcrete are very similar. Officially, both are called shotcrete, but one is known as wet gun shotcrete and the other is dry gun shotcrete. This crew had a gunnite (dry gun) rig, but for my job, they chose to do shotcrete for a variety of reasons. I think there is another comment on here somewhere that I explain all that. I hired them back one more time and then found another crew to do the 4th phase of the house. That latest crew did use gunnite, so those videos are coming eventually.
Simon HomeintheEarth Thanks. yes I did see that comment afterwards. Gunnite gives a much higher strength much earlier thereby reducing the risk of failure or sloughing before setting. This is due to the greatly reduced amount of water in the gunnite mixture. Many amazing techniques specific to gunnite were developed during the construction of the Alaska pipeline. The use of gunnite when there are start and stops in application greatly reduces cold joint issues due to the force of which it's applied. A big drawback however is the additional material required due to bounce back from the applied surface. A true gunnite has such a high slump, it is difficult to finish. Shotcrete is good as a cosmetic top coat. In closing, gunnite takes a bit more teamwork skill to apply efficiently over shotcrete. I'll look forward to your gunnite video. Thanks
Yea, we definitely preferred the gunnite job, but I think that was mostly because the crew was just so much better. They actually tried to make it smooth ;^) They cleaned up after themselves, finshed up the wall tops nicely, etc. I had expected more rebound, but actually, there was less than my shotcrete crew. One thing I doubt is the strength. I had heard that gunnite would be stronger, but that depends on the mix. Our gunnite crew basically just mixed basic portland cement with sand in an auger. It just doesn't seem as strong as the mix truck concrete that included flyash and lots of interesting additives. There were a few places where I had to chip off overshoot and the shotcrete is so strong that the fragments kept their edge (like a flint knife). The gunnite concrete just seemed like regular concrete (maybe 2500 psi?)
Simon HomeintheEarth Exactly about the strength. It is the mix that dictates the final strength for both. No magic there. I am saying that the gunnite expresses it much earlier over shotcrete. I've tried premixing fly ash into the gunnite mix but it was too hard for me. Fly ash, if you can get it in bags is an amazing product. It lubricates pump lines, trowels great and when substituted for lime in mortar or stucco, you save the need for primer before paint. In my opinion, using a four bag portland an a one bag fly ash for 2500 psi mix will nearly eliminate slab creep. Two things I guarantee every customer: 1. Concrete will crack. 2. No one will ever steal it. I am impressed by your work.
jesus who did that concrete work??? you never leave gaps in the concrete like that..you go till job is done..no tamping nothing just a quick rub with the trowels..if they did that in my company they be sent packing..its rough as a bears arse,you know that those two different sprays of concrete wont bond.
and curing it in the sun??? wtf man...that looked like it was cooked in a oven...no water sprayed on it?? jesus that concrete crew made me pist off!!! bad crew who ever they were.
We switched to a different crew for this latest section (video not out yet, but you can see the pics on facebook) and the difference is incredible. So nice and smooth I'll feel bad when the time comes to bury it. Also, this new crew used tape measures all the time to ensure consistent depth, cleaned up the edges, etc.
Actually, it just needs to be clean. Then you can apply shotcrete without worrying about a cold joint. The way it is applied makes it very different from poured concrete. Just google "Shotcrete cold joints" if you want proof that they don't form... There is lots of research on this, including engineers looking for them with a microscope after applying fresh shotcrete to 100-year-old concrete. One of the first thing the shotcrete crew boss did was get me to read articles in the shotcrete magazine about this, probably so I wouldn't make this comment when he showed up on my site.
@@SimonHomeintheEarth I bought land in Southern Colorado and are looking for an alternative type building, with thermal mass. Yours is pretty cool 😉. I'd like to see the finish product though. I'll look to see if you've posted those vids. Hey, thanks for your reply!!! 😀
A lot... I have seen the same design hold up very large excavators. When I add the soil, that also helps distribute the load and increases the limit even more. I don't think it is really possible for me to overload this.
Yup, its an idea that has been done in many places, mostly for the military. I have seen fancy setups with a big earth moving belt that pushes the dirt along. They use the conveyor belt to get the dirt in place (plus some heavy equipment) and then turn it on again to push the dirt out again. They can use a relatively short pile of dirt and move it along in one direction over and over again as they cover section by section. On a smaller scale, I once saw a guy who piled up a bunch of hay bales, covered that with rebar and concrete, and then tied a hungry goat up in the door way. The goat cleaned the place out pretty quickly. The guy didn't show how much work it was to clean the goat poop out. Maybe the goat knew to do that outside? ;)
there seem to be many houses going in around you, are they all doing earth style homes? what area of the US are you in? is there building codes, etc..?
The rest of the neighborhood are all custom homes, but none as crazy as me. I do know of 2 other earth sheltered homes within a couple miles, but it is certainly not a common building style here in SE Michigan. Even though we are over a mile back on a dead end road, the road is pretty (it has been used in a car commercial) and I get lots of people drive by just to take a look, most drive away quickly when I wave at them. There are building codes, but they mostly apply to regular homes. For instance, there are no codes that specify the strength of your roof before burial or how you need to make your plastic umbrella. Instead, the inspectors just want to know the plan was engineered and that I am following the engineered plan. My building inspector said he thinks his job is to make sure the builder makes a home that is good for the home owner... Since I am both, we have a pretty friendly relationship.
Also I don't get it, why not dig a proper hole and build in it rather than this. Also a Cylinder doesn't hold as compression in that direction/dimension as it does on the transversal.
Why rebar? Doesn't the arch structure take care to keep the concrete in compression? Rebar is used when reinforced concrete will encounter tension conditions. An arch is always in compression so I argue that the rebar is a big mistake.
I would argue that the rebar isn't needed for an arch structure under pure compression, but also that defying the building inspector is also a bad idea. To get the house built, I had to get my plans approved by an engineer and the building inspectors. They specified the rebar requirements. It certainly didn't hurt to add it, except for the cost of 2 tons of rebar. It probably did help keep the shotcrete from sliding down, so that was helpful.
I have answered this question a bunch of times in the comments already, but we will go one more time... If I factor in footings, floor, quonset, end walls, rebar, shotcrete, waterproofing, electrical (rough and final), plumbing (roughed in bathroom) and garage doors, it came to ~28$ per square foot. I don't even want to admit what the stucco added because it is out of proportion to how thin a layer it is. The final thing was adding the earth, which cost me a few dollars more per square foot. The couple basic skylights and 2 standard windows that I have yet to add will be hardly noticeable and the earth-sheltered garage is done for under 40$/sqft. The rest of the house has some more expensive features and was budgeted at just under 80$/sqft, but we are a little over budget and will probably end up in the 90's if things continue on their current trajectory.
Of course they did... And yes, I agree, but they were the only ones who would do the job. One positive thing I can say about their work is that concrete is very very strong. Ugly as heck and I am sure they ripped me off on the cost, but man is it strong.
Two tons actually... Personally (I am an engineer also), I think that any reinforcement was unnecessary because the concrete is in compression anyway. But, in order to get it built in my over regulated blue county, I had to get an official engineer to sign it. So I went with the Rebar size and distribution that I found used on many other earth sheltered homes. I had several copies of plans from "form works" and used their pattern to speed things up with engineering approval. It costs about $1000 per ton, so paying an extra $2k for materials is actually cheaper than paying an engineer to prove to himself that I don't need it.
Nope. Concrete is very cheap and I didn't need plywood or shingles or siding, etc. The entire house project has come in at under 95$ per square foot, but that quonset garage, with its bathroom, electrical, windows, garage doors, shotcrete, etc. came in at $28/sqft. This makes it about the same cost as a low end pole barn in my area.
bei 05:30 die vorgespritzte Mörtelschicht glatt ziehen ist falsch, die Oberfläche wird glatt und die nächste Mörtelschicht hält nicht mehr so gut wie sie soll. Es entstehen zwei Schichten die man aber nicht will. at 05:30 the pre-injected mortar layer is smooth, the surface is smooth and the next mortar layer is no longer as good as it should. There are two layers that you do not want.
Yeah you need to use a rubber seal from the foundation to the arches that end up connecting and seal to prevent any water from entering the structure at the cold joint....
I am a bit tired of saying this in the comments, and I think I even mentioned it in the video, but I'll give it another go... You don't have to worry about cold joints with shotcrete because of the way the molecules collided during the application process. You can look up articles on line where they literally put shotcrete over 100 year old concrete and then cut it in half, polish and try to find the cold joint with a microscope. Its not a problem. To viking shelter's point, I do wish I had put more seals along the bottom of the ICF walls (poured concrete) and ended up needing to go back and fix that in a more difficult way later. But none of the shotcrete walls or joints have ever had any problems at all.
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I loved this so much. No blah, blah, introductions and bs. Just quick simple explanations.
johnknoefler I loved that too. Mostly just the facts except for the guys dying folklore story. But even that was fast and clear. Usually I put these all on mute.
I keep having visions while i am awake of this structure. I just came a accross this video now
I love how this sounds like a Wes Anderson film.
During the Vietnam war it was very common to build hardened aircraft shelters using the very same methods your using for your garage. The difference was the ends were left open some planes could taxi in one side and out the other. A rocket attack could land in front of a entrance and take out a plane. But shelters on either side would be untouched.
A friend of mine built these shelters and he said they could absorb a 120 mm rocket attack without any issues.
He also said they used slip forms for construction but other methods were also used.
yeah right. controlled demolition.
David Micheletti I
Go to WoodPrix webpage if you'd like to know how to build it. Good solutions for everyone I think
Quonset hut reminds me of my basic training at USMRD San Diego during the Vietnam Era. The Quonset hut was hotter than hell and a heat magnet. Thanks, but no thanks, I would live in something else these days just because of the memories.
@@jarmstrong2843 understandable
I was surprised it didn't collapse. 40 yards is a lot of weight plus the rebar. Well done 👏
That's the best steel arch building job I've ever seen outside of military construction. Concrete was a great idea.
That's not a q-hut, that's a damn bunker! Pretty impressive!
Amazing had 2 HS friends lived in recycle ww2 Q/hut thought then & now neatest ever House 2 Have ! TY 4 fond memories ;)
There is a House on Lake Tyler in Texas that was built in the 70's with this method. (North side of the lake near the center) They poured their foundation smoothed it out and then shoved rebar into the setting concrete foundation. After it set up they started adding rebar to the upright rebar and just started forming it over into dome shapes and tied it all together. They built windows by tying a hole in the side with rebar. Bolted a 2 x 4 block to the rebar at the bottom there they wanted the windows, then set a thick piece of tinted plexiglass over the hole openings. Leaving the paper covering on the plexiglass. Doors were framed the same way. Then they wrapped the entire 5 room structure in burlap and tied it to the rebar. All wirring was installed in conduit and switch boxes tied to the burlap and rebar. After shooting a lite coating of pool plaster against the burlap covered walls they waited fot it to set. Then went to town with the gunnite sprayer.The plexi winmdows were uncovered later in an oval shape. Since no windows, but the kitchen window over the sink opened to the outside and the house was so insulated and air tight, they had to install a dryer vent through the doors, just so they could close the doors. From the lake it looks ike a flying saucer at night when they have the outdoor lighting on. Was my wifes Uncles family that built it. Been inside it a few times when we went to the lake to go water skiing. He told me his air conditioner was just a small 3 ton unit, with a built in de humidifier in it, and his electric bill was almost nothing. Very nice and cozy inside. Lots of light but no heat through the windows. Like living in an Ice Chest!
You make it sound so easy, but I can assure you that it was a lot of work ;) I looked around the lake on google maps, but couldn't quite find it.
I have been waiting for this vid ever since you started the quonset hut.
I have been in the gunite- swimming pool business since college. I have four decades of experience with 7.5 sack gunite and wet shotcrete. The pictures show a fine job and the naysayers are simply wrong. Lack of knowledge is all over the web. Some folks should know what they talking about before they chime in!
I also been shotcreting pools fir 20+ years, they were just ok imo. Didn't get shit done dayv1 because they lacked experience in stacking the mud imo. It was OK, but I'm certain their is voids where the mud fell, the pladtic didn't do them any favors on being able to stack it up.
Nice concept. I once saw a documentary that showed how the nazis made so many hangars as fast as they did. They would put down a conveyor and make large mounds of pea gravel over them, lay rebar and concrete, then once hardened they would turn on the conveyors to remove or advance the gravel depending on if they were or were not going to continue adding length to the structure.
I saw one guy on the internet piled up a bunch of hay bales in the shape he wanted, covered it in concrete, and then tied a goat (or maybe it was a cow?) up to the open doorway. The goat cleared it out for him.
Simon HomeintheEarth Lol! That would work too.
Now those boys (n gal) are not afraid of work. That is a lot of work ! Well done, Amazing.
This vid should be shown in the Dept. of Human Services Admin (Welfare) waiting rooms.
the strong structure is the good team work
Yes, a Manlift is definitely a worthwhile investment.
the termite union isnt going to be happy !
Excellent, excellent, excellent.
Simon, maybe showing the football team how to construct a house will help the growth of earth sheltered and bermed houses in future. Nothing wrong with thinking or building outside of the box (pun intended).
No blow pipe to blow excess rock away from the wall to prevent rock pockets. It's a very important part of proper shotcrete.
...wait a minute... insulate the OUTSIDE of the quanset hut.... OMG this is genius...
As you may already know ferro-cement construction should be applied monolithically.
Many may not know or realize that ferro-cement construction was essential part of ship building during WWII.
Thanks for the video.
If you are referring to the cold joints... This is not quite the same as ferro-cement, this is shotcrete. Google "shotcrete cold joints" to see how the way shotcrete is applied actually slams the molecules together and there is no cold joint. You can find lots of civil engineering papers on the subject, most of which involve a microscope to try and find the cold joint.
This isn't ferro-cement, this is shotctete. There is no such thing as a "cold joint" in shotcrete or gunite if properly cleaned and prepped. The individual pieces of sand/aggregate change shapes when shot and everything gets interlocked and filled in. Hard to explain without an illustration
@SimonHomeintheEarth u are absolutely correct, tge best way it was ever described to me was that tge individual pieces of sand and rock are shot at such a velocity that they will change shapes and everything gets locked in that way. Like shooting puzzle pieces that change their shape to fit in where it's shot, everything get interlocked
First off, GREAT video (really, the whole series). There's quite a few DIY videos that either give TOO much information, or not enough, or miss/mis-explain certain steps, etc. As I guy trying to learn about this particular type of project, your approach to the video-making is terrific. Thanks.
One question, apologies if maybe you've addressed this somewhere else: Looking back on the project, do you know what the cost/time/efficiency differences there might have been if you'd have just made an ICF house throughout vs. using the Quonset hut? Thanks in advance.
Glad you like it. My favorite comment so far was that a viewer hated time lapse videos and, "could I just show the whole thing?" I said that would probably be a very long youtube video. ;^) She made the same comment on another video, so I said it wasn't time lapse, we just work really fast. ;^). But seriously though, for my own personal mental health, it does feel great after a long week(s) of what seems like slow progress to suddenly see it move so quickly in the time lapse. Even the most difficult and frustrating day suddenly seems so easy and productive. My wife is actually a little bit worried that someone out there may think it is easy and attempt something similar.
@@SimonHomeintheEarth Just tell them to watch at .25 speed.
A couple of suggestions; It would be better to have finished one bay from start to finish in the spraying of concrete. Its not a good idea to have a cold joint in concrete as that is where it will break in any kind of seismic event. Also it will let in moisture and eventually the rebar will start to spaul out. In the future you might consider lightweight concrete if you have pumice in the area, I also would add in some fiber to that mix to get better confinement of the rebar. Finally I would use some "chairs" to support the rebar where it was touching the quonset hut. Rebar needs good coverage or it will just fail under load conditions and break out of the concrete. Probably at least a couple of inches of coverage. It looked to me like the ridge sagged from the first day to the second day of spraying on concrete. There was too much weight in the walls. It might have worked better if you had done one bay at a time and supported the inside while it cured. I didn't see any cylinders, but we require the taking of three or four cylinders of the concrete that are broken at 7, 14, and 28 days to make sure that the concrete has come up to the designed strength.
Shotcrete is not like regular concrete in that the way it is applied prevents cold joints... Google "Shotcrete cold joint" to see lots of engineering papers where they try to find cold-joints with a microscope after shooting on to old concrete. This is why it is used to repair bridges, etc. Also, if the concrete is getting wet, that means my waterproofing has failed and I will be having lots of other issues long before the rebar rusts. I plan to keep the concrete and rebar dry. Pumice is very expensive in my area and, since I want thermal mass and strength, I preferred high strength concrete to light weight concrete anyway. I did add glass fibers in the mix truck though. The shotcrete guy didn't care for it, and complained a bit and said it wouldn't really prevent cracking, but I added a few lbs per yard anyway. It was cool because you just toss the whole bag in because the bag its self is made of glass fibers. We did use hundreds of 1.75 inch rebar chairs to keep the lath away from the rebar and ensure coverage. If you can't see them in the video, just follow the link to the website for detail photos. Not sure what you mean about the sag, but it isn't noticeable in the final structure. There is some quilting between the rebar, but the stucco layer will smooth that out. We had to do it all at once. It would cost far too much to have them come out for each vault. In fact, I have already broken up the job more than I would have liked. I didn't support the inside because it didn't need support and that would have just been extra work and cost. We got plenty of concrete "samples" each day, even if we didn't keep the proper slump tests. Those were very strong and kept a nice sharp edge when we broke them up with a jackhammer. It was rated at something like 8500psi concrete.
8500psi is very strong concrete. My experience with structural shotcrete was doing seismic mitigation work for a school district in Southern California. We filled in classroom windows and thus formed "shear panels" which transfer energy from high in the building to the ground during an earthquake. There were typically 2 or 3 bays per classroom and we would fill in one from column to column. The roofs were concrete slabs and we experimented with building forms, cutting holes in the roof and pumping the concrete into the space. Of course that was after we epoxied in rebar grids to the existing members. Eventually the structural engineer allowed shotcrete, but cold joints were not allowed. Existing concrete has to be wetted down to prevent it sucking the moisture out of the new shotcrete before it is applied. If it dehydrates the shotcrete too fast it will mess up the curing and the strength. We also used an epoxy in some situations to bond the shotcrete to the existing concrete, but generally we relied on the rebar for transference of energy. One of the interesting things about that type of mitigation work is that you create a stronger part of the building and that is where the damage will occur during the next earthquake. The stiffer part of a building will resist the transfer of energy and that is where the cracking will occur. But the stronger building will also buy some time for the kids to get out, or at least that is the hope. Seriously the building looked more egg shaped after you started applying shotcrete in the video, but it have been an optical illusion.
Oh, I thought you were talking about a different video (the bedroom shotcrete). That one used hundreds of rebar chairs. This one only needed about a few dozen rebar chairs to keep the rebar off the steel Quonset. The Quonset did squish quite a bit just walking on it (point load), but because we shotcreted the sides first, the "squish" due to the concrete weight was less than just when a person walked around up there, so I wasn't too worried about it.
Wow that is really cool but I wonder if you could use foamcrete as it would be much lighter and cheaper?
Foamcrete would be lighter, but weight isn't a concern. It is only cheaper if you can find someone setup to do it for a lower price. In my area, the lightcrete guys quoted me about 3 times the price. If I had that sort of extra money, I would have used it to spray foam over the outside of the strong shotcrete.
It didn't collapse. If I was really concerned that it had a significant chance of collapsing, I wouldn't have done it. ;) Or I would have done it with a thinner layer of concrete and then done it again a second time with the previous concrete supporting the weight of the second application.
@@joshblick Given that it's a perfect semicircle the forces almost completely cancel eachother out. Giant concrete sewage pipes are an example. They can hold hundreds of PSI of pressure.
@@00000005547 Semi-circles are not impervious to infinite pressures. Everything has "weight" and gravity does exist. And "giant concrete sewer pipes" are made in forms, not sprayed on a roof. We're not talking about cured concrete, we're talking about the weight of wet concrete.
thanks again for the informative video. i just found out a neighbor of mine is making an in earth home.
Where about and what style?
on a bayou with two story only part that is visible is the side next to the water
Not too many earth sheltered homes out on the bayou. Usually, they are more popular in dry or sandy environments... But if you take the proper precautions, I guess you can do it anywhere.
yeah, he is getting helical piles down for the foundation and then cement and lots of water proofing
SOB. this is exactly what I want to do!!
An example of the kind of house never to build! Very labor intensive and how are you going to ever sell it to anyone else? This is the first video in a series but I have yet to see how you are going to comply with basic codes such as light and ventilation, insulation and engineering using shotcrete to structurally support the weight of earthen cover.
I complied with all building codes (and exceeded them). We have a very active building inspection department. Yes, it was labor intensive, as are many good things in life. Only people interested in a unique, durable and energy efficient home would be interested in buying it. There are many such people in the world, but especially in my county. However I can only sell it once, so I only need one of them to make an offer (when I am ready to sell).
It's a hippie thing.
I love this idea but is there any insulation on the OUTSIDE of the Quonset hut or on top of the concrete before you bury it ? How much condensation are you having inside the structure ?
Yes, I filled the valleys with 4 inches and then added 6 inches over the outside after the concrete, so R40? Plus the dirt and concrete... But yes, in the early summer, when the walls are cold but the outside air is hot and humid, condensation definitely happens. The steel is galvanized, so it doesn't seem to be causing any rust, but condensation does run down.
@@SimonHomeintheEarth What did you do on the ceiling ? Is it bare exposed metal, or covered over ?
- thanks !
Outstanding
Former Landscape Architect....just like building a Gunite Swimming Pool just upside down... I have long been a proponent of Earth Integrated Architecture...
I love it
I like that but what was the total cost after you finished
Hellova innovative project!
Very informative! Did you consider spray polyurethane foam exterior rather than concrete, they have it in different densities and a lot easier to spray?
Yes, I wanted to do that. It would have been a lot nicer. However, the cost was much higher. Sprayfoam in my area, capable of being used in this application, costs about 4 to 6 times the price of quality Foamular 250 rigid insulation and a heck of a lot more than the few little sheets of cheap polystyrene that I used here.
Oh, I see, I thought he meant spray foam over the steel and then add the concrete... If Russell meant instead of concrete, while then I really wanted this thing to be much stronger than spray foam... Although he does have a point. I know of a number of these quonset huts that were buried without the concrete.
Concrete has advantages in fireproofing; with a good earth cover, the place could most lkely come through a firestorm.
The shotcreted steel arch building could likely survive a firestorm. The earth is nice extra insulation but what he effectively built was a small "hardened aircraft shelter" (HAS). By comparison foam would be easily melted and could be heated sufficient to burn. Concrete was the superior choice.
Shotcrete boys let you down a bit ,
Great vid though .
interesting. But I wondered about the shotcrete going on in stages with time gaps rather than in one continuous slower shoot. Won''t the patchy application leave weakened joints and lamination layers.
You can look up studies on "Shotcrete cold joints" to learn more. Basically, the studies apply shotcrete layers years or decades apart (after cleaning the first surface) and then cut a slice and examine the joints with a microscope. Because of the way that shotcrete applies the molecules, they bond on a molecular level and (if done correctly) there is no cold joint. This is why it is used to repair old crumbling bridges, etc.
I read all 250 comments on this video and haven't seen this addressed:
My research into these Quonset kits is the ribs created by the manufacturer's equipment bend the steel to create a total profile dimension of a nominal 7" (depending on the diameter of the structure). You mentioned some 4" foam pieces (looks to be the white expanded stuff) in the top sections to save concrete and weight, but why did you not do this for the entire arch? I also see somewhere you mentioned 6" of concrete, yet don't explain where that thickness is. If it is 6" in the thinnest parts (crown of each rib), then that would be 13" in the gully of the ribs (thickest) where there is no foam. Due to the type of loading for the finished structure, wouldn't a single thickness of 6" throughout be sufficient? Or put a simpler way, if you had used an air inflated form, what thickness would the concrete be?
Yes, I wanted some insulation on the top of the quonset to lower the weight there (I was concerned about the wet weight). It also added some insulation against heat loss where I knew my earth would be thickest. On the sides of the quonset, I wanted lots of concrete for strength and I wanted a better thermal connection with the deep earth, so no need for insulation there.
The 6 inches (roughly) was over the top of quonset, over the thinnest part. In the deep parts, you could add 7 inches and get to 13 inches, on the sides, they probably got several inches thicker than that. Yes, a single thickness of 6 inches would have been sufficient. Even 1 inch would be sufficient if placed correctly (I know of larger underground houses than mine that are only one inch thick), but the engineer was concerned about the skill of the shotcrete crew and wanted 6 inches to be safe. I agree that it would have been overly optimistic to expect the crew to follow the shape of the quonset precisely to give a uniform thickness.
Much of how these things turn out is a series of compromises. But concrete is relatively cheap (~$100 per cubic yard that can cover 81 sqft at 6 inches thick) compared to the labor to place it in a fancy way. Concrete is even cheaper than the insulation per inch.
If money was not a concern and labor was fully available, I would have liked to use spray foam to completely cover and protect the building and then shot six inches (or more) of concrete over that.
@@SimonHomeintheEarth Thanks for the response, I am planning on doing a 40' underground arch building using a Quonset as a form and you were the first I have seen do one below grade. Mine is in neighboring Lenawee County and I hoped to start it this year, but I'm getting a late start for the season. Will also build a round 2-story underground house (we think similarly independently) the following year (hopefully): th-cam.com/video/2LcGbi8_yoA/w-d-xo.html
What if you use this for a bridge? Over a river. Like the river would run through the opening.
Cover in rebar mesh, then spray concrete.
Perhaps, a thicker layer of concrete would be needed.
Yup, I think it is done this way pretty often, maybe using something cheaper than a Quonset hut.
Thing is, you wouldn't need as many sections as you need for making a shelter. That's if you're making a bridge for a farm, a small bridge. 10 feet wide.
I'm still researching this...
So far cement bases on each side of the river, connected by H beams made of steel, covered by more steel, and a layer of reinforced concrete, seems to be, not the cheapest, but the best bang for your buck.
Yes, pretty confident it would work. Span matters a lot though. If the span is wide, you need to be more concerned with different materials expanding and contracting with temp variation... A cheaper way (and you can find lots of youtube videos for this) would be to just use a wood form instead of the Quonset hut. Then you just rip it out after the concrete setsand don't need to worry about the steel expansion or rust, etc.
You're the only one I can find placing shotcrete on the outside of one of these. Did you consult with the manufacturer about it? And where did you learn about the shot create? Thanks
Yes, and the company told me very clearly that they were not engineered to be buried, and then someone at the company sent me a separate email with pictures of a bunch of their Quonsets that people had buried anyway. However, they were all "direct" burial examples. I was just using the quonset as fancy formwork. It was far more than strong enough to carry the concrete load while the concrete set. Now it isn't under any significant load and the concrete is taking the earth load. When we shot the quonset, it deformed less than when we had someone (a point load) walking on it.
I forget where I learned about shotcrete. I had read a lot of books (pre TH-cam).
I did also need to have the structure officially engineered in order to get the building permit in my area.
Faster, cheaper, better insulated & stronger to just spray a monolithic dome in that shape. Also, drop the steel rebar and use basalt rebar. MUCH better.
Hey Patrick, Where is your data or what is your experience with alternatives?
Putting up a Quonset hut was pretty fast (2 Fridays and two Saturdays by amateurs). The rebar was another couple Saturdays and none of the people involved had ever touched rebar before this project. Shotcrete was two more days (by pros who told me they would not take any job that required shooting from the inside as with a monolithic dome). You ever heard of a monolithic dome going up in that few amateur man hours?
Cheaper? The structural part of this (footings, Quonset steel, rebar and shotcrete) cost maybe 17$/square foot. How much for a monolithic dome?
Better insulated? That is an independent issue since I could put the same spray foam as would be used in a monolithic dome on the inside of my quonset, but I chose not to because it costs a lot more (and would make the inside ugly). Instead, I put 4 to 8 inches of Rigid insulation (R20 to R40) and at least 3 ft of earth over mine. I'll bet that is better than the average monolithic dome, traps more thermal mass and costs less.
Stronger? I doubt it, but I am open to discussion. It would depend on things like the thickness and formulation of concrete, rebar layout, etc. The shape also matters, but only if the loading around it is optimal to that shape (as it is for my buried quonset). People who talk about how strong an egg shape is often forget that eggs are also very easily cracked open.
As for steel rebar vs Basalt... I have used both on this project and each has their own advantages. In my area, Basalt costs nearly 30% more per length (assuming I use 3/16ths basalt to compare with half inch rebar). It is great in terms of ease of moving it or curving it, but it has very little structural stiffness. This makes it great for following the curve of an air form or against the dirt in a gunite pool, but pretty useless for the sort of 3D flying concrete I do on most of my construction.
Finally... Choice. A monolithic dome wasn't want I wanted (architecturally), if you want one, then you build one. It was also the only building type prohibited in my area because neighbors think it is ugly.
I love how you destroy their nonsense.
I hear good report on using Hempcrete.
Hempcrete is a fun idea, but it is not nearly as good as the proponents say it is. It is less than 1/10th the strength of concrete, so it can only be used as a fill wall. You usually see post and beam structure to carry the loads and then just unistructural hempcrete to fill the spaces between the structure. It is also difficult to find a supplier. I wanted to experiment with it a little, but, even in my rather liberal area where every 2nd billboard is for an mj shop and they even advertise cdb oil for pets, I couldn't find a supplier who could sell me the hemp, either mixed as hempcrete or on its own.
Hello. I am curious if a quonset hut can be nested inside of a larger quonset hut, with concrete of some type between the two? If the huts had sufficient thickness metal, would they be able to act as the rebar for the crete? Just thinking out loud, have no engineering degree or anything. What do you think? I see the actual hut seems to be the least expense of this style of building, so ...
Thanks.
Grey
I don't think you need the outer Quonset hut (and it would probably be very difficult to add). Also the Quonset in this case was $7K, the rebar was $2K, so the rebar would be cheaper than the outer layer of Quonset... Or, depending on your need, you could just use the Quonset and skip on the rebar. Even for buried Quonset huts, Most don't use concrete, they just bury the steel directly, but then you need to get the thicker steel for the Quonset, so that raises your price a bit.
I see. I was thinking the rebar plus labor would be more than the quonset. Thanks for your reply, Simon. I will look at more of your vids to see more of this project. Take care,
Grey
The labor for putting up the single quonset was also much greater than the labor for the rebar. I would assume that putting up a second quonset (before or after the concrete between) would be considerably more difficult. Not sure how you would reach to tighten the bolts.
I was thinking more along the lines of using the two sizes as the form for the concrete. Either slide the larger over the smaller (on rollers) after they were constructed and fill with crete from the top through pre-cut fill holes, or pre-casting sections much like you made your arches, only using sections of the quonset huts as the form. Using this method would also entail some sort of large jig and need a way to lock the pieces together once erected. Just some thoughts, not defending them as better or even plausible, but I wanted to explain what I was thinking. Thanks, Simon.
Grey
Yup, all sounds much more difficult than just using rebar to me... Although the precast arches idea sounds interesting, you would still need the rebar inside.
From an engineering perspective, the rebar gives the concrete tensile strength because loads are transferred to the steel before the concrete can deform enough to crack. The rebar is rough to improve its connection with the concrete. I don't think the concrete would be very able to transfer its tensile loads to the smooth Quonset hut steel and would probably just separate from it instead. I suppose maybe you could "rough up" the quonset hut, but then you would risk ruining the galvanizing (and the quonset would rust) and that also sounds more difficult than just using rebar.
Well if California had this building concept 3000 houses would not have burned
that depends....
Yeah but they would have taken 5 years to build , 12,000 dollars in payoffs and bribes and the union would have sued even though they dont do that kind of work or want to , at the end it would cost 1,297,065 dollars and housed refugees .
I noticed in the time lapse, the forks on the front loader were going down. Are the seals going bad? I operated an old Case 570 backhoe with bad seals on the boom. It dripped so bad, I took several gallons of hydraulic fluid to fill it.
Yes, it goes down very slowly after I turn it off. The problem is better now then it was when the video was made. I opened up the front and found one of the cylinders between the front pedals was leaking just a tiny bit. Tightening the connection was enough to solve that problem. I have not found any other leaks and the hydraulic fluid levels have not gone down in the year since. I figure maybe the leak is just back thru the hydraulic pump? Anyway, I don't have time to deal with that problem and prefer to think of it as the "skid steer is putting its self away".
This is extremely scary how you did this tbh.... how is it going now? Has it leaked?
Its going well, no leaks and excellent temperature control. My only wish is that I had built two of them because I want more room in my workshop.
I love it! Thanks for sharing your project. I do wonder about what the square footage of the finished structure underground will be? Also what is the projected costing, especially compared to conventional construction? I do wonder if you're aware how this might hold up in even colder climates further north (I'm in Canada)? By the way, I'm saddened and embarrassed for you having to entertain so many stupid comments along with some very great ones.
Yea, the trolls are on the internet. Actually, I am Canadian, but living in Michigan now. As for this sort of construction, it is actually very affordable. You pay more for foundation, etc. but concrete is cheaper than wood and I won't need to put siding or brick on the outside. I am sure my home will cost less per square ft than my neighbors, but I do help with a lot of sweat equity. As for this type of construction in canada, look up Bill Lishman, the Canadian inventor/artist and Father Goose guy that they made the movie about. He lives in a house like this that is so unusual they didn't even try to replicate it for the movie. This is in Ontario somewhere. goo.gl/iWgRcC
Thanks for the update...coincidentally I live within a short drive of the Lishman House which the family has placed on local home tours for public view, I'll have to join the next one. Good luck with the rest of your project and keep us in the loop with more videos.
The more extreme the climate (hot or cold, but maybe not wet), the more sense it makes to tuck underground and wrap your home in thermal mass.
Have you had any cracks since the video was made? Hurricane Micheal leveled my shop and this looks like a good way to keep that from happening again.
Nope, no problems with the Quonset hut. The only issue is that its wall are cool, so when you let in hot humid summer air, the quonset cools them off and water condenses on the inside. This makes the floor by the walls a bit damp on hot and humid days. This could be prevented by not letting in so much humid air... Or by letting it in more so that the walls warm up to ambient temps more quickly.
Wow you didn't spray foam the quonset hunt first??
Nope. Two main reasons why. First off, I wanted a good thermal connection with the earth. If you insulate the structure too well, you lose that earth moderating effect. I did put insulation in the crenelations (so half insulated with 8 inches), but that was more to reduce the concrete weight and still left half the surface area open for heat exchange. Secondly, the cost of spray foam is pretty extreme, especially if you mean the kind that can support the weight of wet concrete without crushing. I priced it out (just out of curiosity) and it would have been the most expensive line item in the build by a wide margin. More expensive than the steel. More expensive than the concrete. And it would have hurt thermal performance... No thanks.
WHy not just lay on cloth concrete and water it
down?
This is considerably stronger than "cloth concrete", both because it is better mixed and because it is much thicker and rebar reinforced.
Offering monolithic concrete homes in Florida same design but will create a foam shell to shoot against from inside eliminating the steel building good luck nice solid home and like the faugh front might need to steal it.
Yea, on other parts of the build, I wanted to shoot from underneath against a form, but I couldn't find a single crew in my tri-state area that was willing to shoot from underneath. It is messy work and no one wanted to do it. I did consider importing a crew from down south, but couldn't afford it.
@@SimonHomeintheEarth tunnel contractors currently training crew to shoot from inside against foam shell stay safe nice completion.
I would have waterproofed the sky lights.
That OSB won't hold up to water.
And that finish crew did suck. Good thing you got a different crew
The OSB was just temporary, I have already removed it. It was fine under the concrete. I had put the shiny side out and I think it does have some sort of mildly waterproof coating built right in. Actually, some of the boards even had some sort of shiny plastic foil on one side.
I've loved watching this come together over the past few years. Any guesses on completion date now that you're getting closer?
I would love to have it all closed in by the end of 2017, but it is tough to plan that far away because each new phase has a learning curve and ends up taking longer than I thought it would. Instead, I try to plan smaller steps. For instance, I am fairly confident that we can get the next phase of shotcrete up before the end of May, which would mean we may be able to have the house 2/3rds buried before the end of April. But then I start on the rebar for the radial vaults on the center third, and that is a whole new ball game, so it is hard to predict how long before I could shotcrete that, etc.
Is the building reinforced on the inside? That quonset hut have the collateral load to handle the weight of the concrete and rebar ?
Nope, we didn't reinforce it at all. Officially, it has a snow load capacity of 75 lbs per sqft, but the engineer's were not able to clearly tell me what that really meant. They just kept saying "75 lbs per square ft... Seventy - five - pounds - per - square - ft... but they couldn't tell me if the load was always vertical, if it could handle load just along the top without the sides also being supported, etc. Anyway, I knew of some others that had put even more load on theirs, so I just went for it.
If we had started by applying the concrete to the top of this thing, then the building would have had to take the full weight of it and I am not sure how well that would have worked out. But we actually put the shotcrete on the footing, so the weight wasn't nearly as much on the building its self. So the first 6 ft have no load on the building... Then after that, it forms an arch, which carries most of the load. The building was just fancy formwork. Shotcrete sets up very quickly, and once self supporting, we could have removed (it would require magic) the quonset and the concrete would have stayed up anyway (without requiring magic).
How much did it cost?
Why didn't you spray foam before concrete?
Costs ended up (at the end of it when we moved in well past this point in the video) at about $92 per square ft. I didn't spray foam first because the kind of high psi foam that you can use in that application is considerably more expensive (6x) than sheets of XPS... I would have done it that way if the cost were closer.
Those boys never shotcreted before.
How thick is the concrete? Can it retain a 30 foot hillside?
Ahh the good old day before camera drones.
Yea, one of those would really spice up my videos. I have a couple friends with decent drones but have not managed to rope them into filming something for me.
This was done in the present day of Camera Drones.
Welding rebar is a bad practice as it affects the tensile strength and will create a weak point of failure. Here in PA PENNDot specifically required wire tying only.
I think I commented on a similar comment elsewhere. Yes, welding can change the material properties of the steel, reducing ductility especially, but if you check the rules (probably also in PA), they actually have a lot of exceptions. For instance, you can "preheat" your welds, etc. In my case, I didn't need to pre-heat (those rules kick in for thicker rebar), also, I was using low Carbon rebar (it is stamped with a "w" on it, meaning, it is safe for welding. Also, in my structure, all the concrete is in compression all the time. By using vaults and arches, the house was designed without any concrete in significant tension. The inpector reviewed my situation and green lighted welding. It really helps a lot because we are climbing all over it (welded rebar is safer), but also because the shotcrete can't vibrate the welded rebar and cause other problems (such as voids).
I agree. Wiring takes longer but is safer.
Wiring is "safer" in terms of leaving the ductility, etc. of the rebar so that it won't fail under extreme flexing or tension... However, my design shouldn't have either of those, especially not on the skylight rebar where the primary reason for the rebar is just for holding up the shotcrete. I didn't weld any of the other garage rebar. I did weld rebar in other areas of the build (such as the bedroom vaults), even though it took extra time, because I was more concerned about the stiffness of the assembly with my crew and the shotcrete guys climbing all over it (actual "safety"). Also, with the formwork tied to the shotcrete, the impact frequency can cause tied rebar to shake quite a bit more. If the shaking doesn't cause the shotcrete to bounce right off, it can still leave internal voids... And those would be worse structurally (both compression and tension) then the welding. Again, this was not a problem on the garage where the formwork was the quonset hut and would not vibrate the rebar. These are all tradeoffs.
It's still standard to build newer generation HAS that way. The interior steel spall liner is much heavier than the Steelmaster building (it is NOT a Quonset hut, that has specific meaning and none of that now-obsolete framed style building are in production today) but the principle is the same.
HAS?
HOLY FORT KNOCKS
a wildfire cant destroy that can it?
What if you just did spray foam on the interior and don't do concrete on the exterior. Metal is strong enough right? What gauge did you get?
Yes, someone from the company (unofficially) sent me a number of pictures of quonset huts that were burried directly without any concrete... But those were the much heavier grade quonsets. I was using the 22 gauge one. I think it was rated for a 75lb snow load.
What bag mix or psi was used? Any admixture, Fly ash, etc?
Yea, fly ash for sure. In some shoots we also used fiberglass or basalt fibers. The concrete tests rated it from 4500 to 8500 psi (some variations)
@@SimonHomeintheEarth thanks
Nice 👍🏼
I am still surprised that the rebar in the US and Brittany is placed in single bars? Why not using rebar netting much faster to work with an more support!?
You can buy welded wire mesh (WWR) on 6 inch spacing. I had used that for the slab reinforcement, but it would be insufficient for this. That rebar is about 1/8th of an inch thick and the sheets still get heavy and awkward. I can't imagine how I could move a net of rebar made of half inch thick steel bars... I literally put in 4,000 lbs of rebar on this building. Even if I could get a net that would be spaced according to the engineers specifications, and even if it only covered a quarter of the building per net, that would still mean trying to position 1000 lb rebar nets... And curve them at the same time? I was not equipped for that. Sometimes it is just easier to put the rebar in one piece at a time.
Are you talking about thin little welded wire nets or do you actually use nets of half inch rebar in your area?
It's mostly 1/8th netting, with 2 it's easy to place, you can even buy pre-bend mesh for wall's and columns.
Yup, I used that elsewhere, but the engineer specified thicker rebar for this area.
Insufficient strength Arend.
Back to the original comment on this thread... I can see the convenience of using WWR (welded wire reinforcement) as it is called here in the USA, but to be clear, smooth 1/8th inch thick wire, spaced every six inches is not stronger (does not provide more support) than half inch rebar spaced 1 ft apart. Its not even close. Also, the reinforcement of the concrete on this Quonset hut has a huge factor of safety more than the strength required to hold up the expected loads (both static and dynamic).
I'm thinking about doing this Simon
.how much can I expect to pay ? I'm thinking of 40×30×16 ball park would be great.and I think this would make it hurricane proof .
I think I wrote the break down several times in the comments. In the end, it was something like ~$30 per square ft. The steel Quonset was only $7000, delivered. Concrete flatwork was 3$/sqft, plus the cost of concrete, etc.
Thanks Simon ..one more question..I was going to sink both sides of the hut into the concrete slab..instead of the track system they offer what do you think.and thanks again..mine will be near the coast,. I have calculated what I think is on the high side 40000 plus my lot.
@@o9rgeronimo979 Missed this one a year ago... How did your project go? For anyone else that sees this... You want to build on some solid concrete, not build the Quonset hut and then pour the slab around it. I thought the track system was too expensive, so I did the concrete groove trick and then grouted it in. Videos of that are all on TH-cam.
Wow, that's great!
How much more expensive is this method of construction compared to traditional methods?
I'll answer three ways... If you mean this portion of the build (Quonset covered in concrete and buried), it was very cheap. With the steel, electrical, a small bathroom, doors, windows, rebar, concrete, etc. It cost less than 30$ per square foot to build. A regular house costs about 250$/sqft. If you mean the entire project, portions of which are rebar cages with shotcrete, etc. then we are in the ninety something range, but we are building it ourselves, so not fair to compare with costs that include all the labor. If you mean an earth sheltered home, built by hired workers, then companies like "formworks" or "terradome" claim those cost about 3% more than an equivalent above ground home. Of course, that extra cost is quickly saved in reduced heating and cooling.
is it asking too much to look at engineering specs for your burried Quonset hut section? Everyone I talk to here in New York tells me it can't be done. I show them your video and they say your structure won't last. I've been following your progress for years and it's the most amazing thing. I have a Quonset hut on its way now and I'm looking to mimic what you've done So that I can Have a big enough space to work in the winter without spending a fortune on heat.
Why wouldn't it last? Once the concrete is on there, the quonset isn't even taking any load. It could rust away to dust and I'd still have a thick reinforced concrete structure.
But sure, email me or facebook me and I'll get you that page of the engineering plans. It is pretty basic. Just some rebar spacing. What gauge is your quonset?
@@SimonHomeintheEarth Thanks for getting back to me! I couldn't agree more. The steel is pointless after the concrete dries. NYS and especially my township, are completely devoid of imagination. If they've never seen it before, it can't be real. What email address should I use for you? the quonset is 18 gauge.
My Quonset is thinner than that. I think 20 or 22 gauge. Actually there is another guy on here (ForbiddTV) that plans to build one this summer. He plans to shoot over a Quonset hut built in reverse (overlaps and bolts backward) so he can take it apart from the inside and reuse it as formwork over and over again. He has a TH-cam channel and I am looking forward to seeing how that works out.
@@SimonHomeintheEarth wow that's crazy!
How much rebar did you use & what was the total cost of rebar? Thanks!
I think I mentioned it in the video, but it was about 2 tons of rebar over the outside of the quonset hut. (not including the walls or floor). I pay about 1000$ per ton, delivered.
surprized not all over NW &ca due to fireproof nuff of them. So jealous of those that git 2 live N them !!
reason I said above lived N Bend Or. when fire blazed thru town N 80s causing many homes 2 burn up I was woodland FF & taught wife & kids 2 git & house down everything yard home fence etc. thkfully fire stopped 1 block fm Us when wind shifted. I was outa state fighting roundtop fire N montana !
Yea, you'd think the insurance company would give me a break since the place is pretty much disaster-proof, but nope. They just smile and take my money. ;)
this reminds me of king of the hill
Why wouldn't you want to apply the concrete directly to the steel and have it bond? You could probably have even welded studs to the steel for extra bond.
Because of corrosion. The bond would be great at first, but eventually, I would expect to see corrosion coming thru the inside. Concrete holds moisture, leaks salts, etc. Not good for steel. It was just safer to keep the concrete off the steel. The shape of the concrete matches the steel and it is very thick and heavy, so I don't expect it to fall off anytime soon anyway.
what sources did you use for your research i been looking for qounset huts that are buried and the only one i found was yours thanks
I don't actually know anyone else who has done it the way I did it, but I have seen pics of directly buried Quonset huts (without the shotcrete) and I have heard stories of others covering them in concrete. But nothing "concrete" enough for me to give you a link to a specific instance. The Quonset hut vendors told me that it is not engineered for burial and that what I planned to do would void my warranty.
@@SimonHomeintheEarth oh ok but once the concrete dry the qounset huts not supporting the weight anymore correct
@@pete1534 Correct. The Quonset is just fancy formwork that I am leaving in place. The concrete arch is self supporting.
@@SimonHomeintheEarth hows the moisture inside could some one live in it buried
Sorry, I guess once a video has too many comments, TH-cam just stops telling me about new ones. But in answer to this question...
It is quite nice inside. Yes, you could live there (just not at my place ;) , get your own). The only moisture problem is when I open up all the garage doors and let in the humid air in early summer. The quonset walls are still relatively cool compared to the hot humid air, at least they are below the dew point, and moisture condenses and runs down. The walls are galvanized, so it's not causing any real problem, but it does happen. Keeping the doors closed on hot humid days and letting in air via an earth tube instead will solve the problem. The rest of the year is fine. In winter, the walls are much warmer than the incoming air and in late summer/fall, they are warmer than the dew point.
How wide is the quonset hut? How thick is the shotcrete? What gauge metal was the hut?
Quonset hut is 30 wide by 40 long. 20 gauge steel. Shotcrete thickness varies because the crenelations are 7 inches deep, but the thinnest is 4 inches thick. Probably well over a ft thick at the base. Also 2 tons of rebar.
@@SimonHomeintheEarth great, thanks. I'm pouring footing next week
Any reason to not use welded mesh for the reinforcing?
The engineer specified this rebar layout. He did also specify WWR with six-inch spacing for the floors, along with rebar. Maybe he just didn't think it was necessary here?
Are you worried about the UV damage on the ICF?
Yes, it did yellow a bit and got a little powder on it. I am sure not much R value was lost, but I was happy to get it all covered in stucco. That would be another video, but we don't have much stucco footage.
better and faster to use rebar-Net it would save you 2 days connecting all those single rebars. and it can easily be layed by 2 persons.
Is the net made up of half inch rebar (as specified by the engineer) or are you talking about WWR (welded wire reinformcement) that is light enough to lift but would not meet the engineer's requirements? I really doubt that a net of sufficiently thick rebar could be moved at all, let alone save me any time.
i have worked with concrete and i builded "Premade" housing structures. we used less than half inch and the buildings where 5 stories high. we used 2 nets and a large "Frame" with 16 mm re bars and tied them with the nets. and also if two person cant handle the nets. just connect it to the skylift and drag it on to the roof. pies of cake. www.armeringdirekt.se/armeringsnat/armeringsnat-12150?gclid=Cj0KCQiAyZLSBRDpARIsAH66VQISPR6Ta8vZdpL1teO8Fj5js8TrGDDh4NCWGGtpcrV09b1u9_LB9wcaAqTNEALw_wcB
and here is an example of a house that we builded www.bendersbyggsystem.se/benders/artikelarkiv/2015/fasadvaggar/
I can imagine situations where using a 20ft long and 300lb net of rebar would be easier than tying your own. For instance, in a factory creating pre-fab panels, but I doubt it would have saved us anytime. All the rebar on this building (2 tons of it) went up in two Saturdays. I would have still needed many of these nets (at least 16 by my calculations) and they would have needed to be positioned and tied together... Nope. A few amateurs with simple rebar and tie wires just seems easier.
A 4 in x 4 in wire 1/4 in mesh would of been easier an stronger then the rebar. but most engineers dont know about it.
why not use Aircrete would have been lighter, insulated and fire resistant. still nice work it's looking good
I did look into aircrete, It is not really structurally strong enough for burial as I plan for my earth-sheltered house, but it would have been a great way to create long-lasting insulating fill, especially to fill the voids between the vaults. However... 1) the only company in my region capable of producing enough at once (lightcrete systems inc) quoted me a ridiculous number. I could have bought all the equipment and started my own company for that much. They were so rude I actually considered doing that just so I could put them out of business. 2) I looked into buying the industrial scale equipment from California, but ended up deciding against it because it would still have been more expensive than using structural concrete (which is much much stronger) and putting 6 inches of rigid xps over it or even just filling all the voids with EPS and putting a thin cap of regular concrete over it. You can make your own rig and use a bottle of Dawn if you are mixing a bucket at a time, but I am doing a concrete truck every hour, so I needed something more industrial scale. 3) I wanted the concrete to have thermal mass and to be able to quickly absorb and transfer heat back and forth with the air inside and the earth under the umbrella outside, so aircrete really wouldn't have been good for that.
So it this rated to withstand a direct hit from a 120mm mortar?
Hopefully that is not a likely scenario. But it should have no trouble with weather.
Great job. Did you consider using the concrete with metal or fibreglass filings in it (like they do in inground swimming pools) rather than the rebar?
In ADDITION to the rebar, yes. Some, but not all, the shotcrete had fiberglass in it. I asked, but my supplier didn't carry the basalt fibers. Those fibers will hold small cracks a bit tighter but are not considered a substitute for rebar in substantial concrete structures like this.
Why not gunnite? Doing that in shotcrete does look risky. nice finish though.
Gunnite and shotcrete are very similar. Officially, both are called shotcrete, but one is known as wet gun shotcrete and the other is dry gun shotcrete. This crew had a gunnite (dry gun) rig, but for my job, they chose to do shotcrete for a variety of reasons. I think there is another comment on here somewhere that I explain all that. I hired them back one more time and then found another crew to do the 4th phase of the house. That latest crew did use gunnite, so those videos are coming eventually.
Simon HomeintheEarth Thanks. yes I did see that comment afterwards. Gunnite gives a much higher strength much earlier thereby reducing the risk of failure or sloughing before setting. This is due to the greatly reduced amount of water in the gunnite mixture. Many amazing techniques specific to gunnite were developed during the construction of the Alaska pipeline. The use of gunnite when there are start and stops in application greatly reduces cold joint issues due to the force of which it's applied. A big drawback however is the additional material required due to bounce back from the applied surface. A true gunnite has such a high slump, it is difficult to finish. Shotcrete is good as a cosmetic top coat. In closing, gunnite takes a bit more teamwork skill to apply efficiently over shotcrete. I'll look forward to your gunnite video. Thanks
Yea, we definitely preferred the gunnite job, but I think that was mostly because the crew was just so much better. They actually tried to make it smooth ;^) They cleaned up after themselves, finshed up the wall tops nicely, etc. I had expected more rebound, but actually, there was less than my shotcrete crew. One thing I doubt is the strength. I had heard that gunnite would be stronger, but that depends on the mix. Our gunnite crew basically just mixed basic portland cement with sand in an auger. It just doesn't seem as strong as the mix truck concrete that included flyash and lots of interesting additives. There were a few places where I had to chip off overshoot and the shotcrete is so strong that the fragments kept their edge (like a flint knife). The gunnite concrete just seemed like regular concrete (maybe 2500 psi?)
Simon HomeintheEarth Exactly about the strength. It is the mix that dictates the final strength for both. No magic there. I am saying that the gunnite expresses it much earlier over shotcrete. I've tried premixing fly ash into the gunnite mix but it was too hard for me. Fly ash, if you can get it in bags is an amazing product. It lubricates pump lines, trowels great and when substituted for lime in mortar or stucco, you save the need for primer before paint. In my opinion, using a four bag portland an a one bag fly ash for 2500 psi mix will nearly eliminate slab creep. Two things I guarantee every customer: 1. Concrete will crack. 2. No one will ever steal it. I am impressed by your work.
jesus who did that concrete work??? you never leave gaps in the concrete like that..you go till job is done..no tamping nothing just a quick rub with the trowels..if they did that in my company they be sent packing..its rough as a bears arse,you know that those two different sprays of concrete wont bond.
and curing it in the sun??? wtf man...that looked like it was cooked in a oven...no water sprayed on it?? jesus that concrete crew made me pist off!!! bad crew who ever they were.
yeah they had no idea what they were doing.
We switched to a different crew for this latest section (video not out yet, but you can see the pics on facebook) and the difference is incredible. So nice and smooth I'll feel bad when the time comes to bury it. Also, this new crew used tape measures all the time to ensure consistent depth, cleaned up the edges, etc.
Spray with PVA solution if the previous run has set: the join is stronger than the concrete.
Actually, it just needs to be clean. Then you can apply shotcrete without worrying about a cold joint. The way it is applied makes it very different from poured concrete. Just google "Shotcrete cold joints" if you want proof that they don't form... There is lots of research on this, including engineers looking for them with a microscope after applying fresh shotcrete to 100-year-old concrete. One of the first thing the shotcrete crew boss did was get me to read articles in the shotcrete magazine about this, probably so I wouldn't make this comment when he showed up on my site.
Is Kip from Napoleon Dynamite narrating this
Getting the sound levels right has been a constant problem. The newer videos (with a new mic) are better.
Can someone tell me how safe and durable is this structure?
Very safe and durable. This is how the military makes bomb proof aircraft hangers.
@@SimonHomeintheEarth I bought land in Southern Colorado and are looking for an alternative type building, with thermal mass. Yours is pretty cool 😉. I'd like to see the finish product though. I'll look to see if you've posted those vids. Hey, thanks for your reply!!! 😀
How much weight can it bear?
A lot... I have seen the same design hold up very large excavators. When I add the soil, that also helps distribute the load and increases the limit even more. I don't think it is really possible for me to overload this.
I've been thinking of shot Crete over long pile of sand. Then remove sand.
Yup, its an idea that has been done in many places, mostly for the military. I have seen fancy setups with a big earth moving belt that pushes the dirt along. They use the conveyor belt to get the dirt in place (plus some heavy equipment) and then turn it on again to push the dirt out again. They can use a relatively short pile of dirt and move it along in one direction over and over again as they cover section by section.
On a smaller scale, I once saw a guy who piled up a bunch of hay bales, covered that with rebar and concrete, and then tied a hungry goat up in the door way. The goat cleaned the place out pretty quickly. The guy didn't show how much work it was to clean the goat poop out. Maybe the goat knew to do that outside? ;)
there seem to be many houses going in around you, are they all doing earth style homes? what area of the US are you in? is there building codes, etc..?
The rest of the neighborhood are all custom homes, but none as crazy as me. I do know of 2 other earth sheltered homes within a couple miles, but it is certainly not a common building style here in SE Michigan. Even though we are over a mile back on a dead end road, the road is pretty (it has been used in a car commercial) and I get lots of people drive by just to take a look, most drive away quickly when I wave at them.
There are building codes, but they mostly apply to regular homes. For instance, there are no codes that specify the strength of your roof before burial or how you need to make your plastic umbrella. Instead, the inspectors just want to know the plan was engineered and that I am following the engineered plan. My building inspector said he thinks his job is to make sure the builder makes a home that is good for the home owner... Since I am both, we have a pretty friendly relationship.
Also I don't get it, why not dig a proper hole and build in it rather than this. Also a Cylinder doesn't hold as compression in that direction/dimension as it does on the transversal.
It is much much easier and cheaper to build and bury than to actually build underground. And in the end, the result is similar.
Why rebar? Doesn't the arch structure take care to keep the concrete in compression? Rebar is used when reinforced concrete will encounter tension conditions. An arch is always in compression so I argue that the rebar is a big mistake.
I would argue that the rebar isn't needed for an arch structure under pure compression, but also that defying the building inspector is also a bad idea. To get the house built, I had to get my plans approved by an engineer and the building inspectors. They specified the rebar requirements. It certainly didn't hurt to add it, except for the cost of 2 tons of rebar. It probably did help keep the shotcrete from sliding down, so that was helpful.
how much was the quanset
7000$ delivered from SteelMaster Buildings
How much does it cost to build something like this
I have answered this question a bunch of times in the comments already, but we will go one more time... If I factor in footings, floor, quonset, end walls, rebar, shotcrete, waterproofing, electrical (rough and final), plumbing (roughed in bathroom) and garage doors, it came to ~28$ per square foot. I don't even want to admit what the stucco added because it is out of proportion to how thin a layer it is. The final thing was adding the earth, which cost me a few dollars more per square foot. The couple basic skylights and 2 standard windows that I have yet to add will be hardly noticeable and the earth-sheltered garage is done for under 40$/sqft. The rest of the house has some more expensive features and was budgeted at just under 80$/sqft, but we are a little over budget and will probably end up in the 90's if things continue on their current trajectory.
@@SimonHomeintheEarth 6 years later I bet that 40 a square foot is 80 now
Looks like a Afghanistan hut but they use mud
Yup, probably helps them stay cool without modern Air Conditioning... Mud may not work too well in rainy Michigan though.
What happened with the audio?
You hired the wrong Shot Crete company. I hope they did not charge you for their waste.
Of course they did... And yes, I agree, but they were the only ones who would do the job. One positive thing I can say about their work is that concrete is very very strong. Ugly as heck and I am sure they ripped me off on the cost, but man is it strong.
ton of rebar. wire mesh no good?
Two tons actually... Personally (I am an engineer also), I think that any reinforcement was unnecessary because the concrete is in compression anyway. But, in order to get it built in my over regulated blue county, I had to get an official engineer to sign it. So I went with the Rebar size and distribution that I found used on many other earth sheltered homes. I had several copies of plans from "form works" and used their pattern to speed things up with engineering approval. It costs about $1000 per ton, so paying an extra $2k for materials is actually cheaper than paying an engineer to prove to himself that I don't need it.
Where are you located?
South East Michigan.
the nozzle man makes or breaks the job, I hope these guys were cheap!
This must have cost a fortune.
Nope. Concrete is very cheap and I didn't need plywood or shingles or siding, etc. The entire house project has come in at under 95$ per square foot, but that quonset garage, with its bathroom, electrical, windows, garage doors, shotcrete, etc. came in at $28/sqft. This makes it about the same cost as a low end pole barn in my area.
@@SimonHomeintheEarth
Thanks for the reply.
I got quotes $135/sq foot for the Quonset kit with delivery. But, that’s it.
bei 05:30 die vorgespritzte Mörtelschicht glatt ziehen ist falsch, die Oberfläche wird glatt und die nächste Mörtelschicht hält nicht mehr so gut wie sie soll. Es entstehen zwei Schichten die man aber nicht will.
at 05:30 the pre-injected mortar layer is smooth, the surface is smooth and the next mortar layer is no longer as good as it should. There are two layers that you do not want.
Just wondering why you are building this bomb shelter ? Seems like a terrible amount of work.
cold joints
Yeah you need to use a rubber seal from the foundation to the arches that end up connecting and seal to prevent any water from entering the structure at the cold joint....
I am a bit tired of saying this in the comments, and I think I even mentioned it in the video, but I'll give it another go... You don't have to worry about cold joints with shotcrete because of the way the molecules collided during the application process. You can look up articles on line where they literally put shotcrete over 100 year old concrete and then cut it in half, polish and try to find the cold joint with a microscope. Its not a problem.
To viking shelter's point, I do wish I had put more seals along the bottom of the ICF walls (poured concrete) and ended up needing to go back and fix that in a more difficult way later. But none of the shotcrete walls or joints have ever had any problems at all.