Your almost 50 and have more energy than this 33 year old! Letting us know the costs is great for those of us that actually care about building a quality, comfortable, long lasting home. Ignore the people that say that's too much!
I have 15 years on you and I really appreciate the fact that this "upgrades" the concrete slab into something that is comfortable to stand on. Thank you!
When you started to talk about the foam with the overlay, the first thought that came into my head was pianos and gun safes. I laughed to myself when you mentioned it a few seconds later.
First, no elephants in the room! So you’ve got that going for you. And the intangible of comfort (and the craftsmanship and thought that goes into it) is worth so much more than the one time cost of producing it. Keep it up, Matt. I think it’s really compelling.
I insulated half of a shed using a similar idea on the floor, and it works, with some caveats. Lots of things I would do differently. And now this video takes what I learned with my shed and takes it up a notch or three. Cool. I'm building a house next summer, and this is how I'm going to do the floor. Thank you, Matt. Great channel.
Matt always stretches my brain to think outside the box. His knowledge and connections benefit so many and make me feel like I’m not completely ignorant when it comes to Texas construction and beyond!!
Man, I wish I had a business partner like this guy. While its nice on one hand to run a business without partnerships, when its someone that has the same love of construction methods, design, and quality then the overall finished product and long term client satisfaction is at a peak. We have developed a good reputation in our area with our clients. All of our work is 100% referrals, and even with the hurdles of 2020 we are still booked out for 8 months with multiple proposals still out.
can this method be used with radiant heating or would the insulation make it useless. can subfloor be put over radiant heated slab with a vapor barrier?
@@gm08351 in-slab radiant wouldn't be effective if you're insulating over top of slab as shown here. You could run radiant piping on top of the new subfloor assembly and it would be more effective than in-slab, since you're not wasting heat on the mass of the concrete... you could also obviously use the electric radiant grid floors that are becoming common.
A way to save a lot of money that I did when building my house was I bought reclaimed foam boards and put them under the concrete. I put 4" of XPS foam under the slab (not the footings) but I did put a 4" XPS thermal break between the footing and the basement slab. I have also used the premade OSB subfloor system that goes on top of the slab. I live in Massachusetts and my basement stays so much warmer than any other basement I have been in here.
@@tomruth9487 usually one or two inches over . You basically create a new floor that is thermally broken from the foundation. You build your internal qalls on the newslab.
I really enjoy all of your videos. I can see your passion for innovative and logical construction styles that focuses the attention to detail. I am a Radon Expert and many of the components you use also help with reducing radon into a building. Thank you and again I really appreciate all your videos and always look forward to new ones. Keep up the good work!
Thanks for pointing out the necessity to get the higher PSI foam if i have an elephant in my house. I almost bought the 10 psi, but just in the nick of time I changed the order to the 16 psi.....its a baby elephant
I actually used this same technique for my new construction in Houston, TX. I skipped out on the insulation board due to cost and used an off-brand T&G OSB floor. I used a 6mil poly plastic as my moisture barrier against the concrete as well. Solid floor solution for sure and it is definitely softer on your feet overall. My main comment is that this is 4x the cost of a typical tar screed subfloor for solid wood floors. My main reason of doing this was to avoid the toxic chemicals used in typical subfloor design. I also used special low VOC glue to connect the floors together. Keep in mind my house if about 1900sqft of flooring.
We've been doing this in basements in Canada for years. Except there are manufactured panels 2'x2' osb with foam laminated to them. They've even gotten better and added air channels in the foam to reduce any moisture that could get trapped.
I've even seen a job done with the following layers in Toronto canada- 10 ml poly, then a dimple foundation wrap layer, then 2" soprema SOPRA-XPS 30, then 3/4" plywood, then flooring. I thought this was overkill.
I am planning on doing something similar to my basement up here in Canada. Only difference is I am putting down DMX 1-step, then foam then plywood. Glad to see I am not out to lunch with the idea of insulating on top of my slab.
I think you are smart to use the DMX or you can use Delta FL. I used the Delta and then 2 sheets of 1/2" osb with wood glue and stapled together. Plywood of course would be better. I glued my flooring down so osb seems to be working ok.
@@saralola3171 Very good video, thanks. With laminating ( I used glue and staples) 2 sheets of 1/2" plywood or osb instead of one layer of t &g material, you can cut down or eliminate entirely having to screw the subfloor down or messing with tongue and groove problems. This is depending on how flat your concrete floor is. The whole new subfloor and new flooring can float and only be held down on the edges by the baseboard. Again this is if your concrete floor is flat enough to start with. A floor leveling material can be used over the concrete if necessary. The whole theory with a dimpled vapor barrier is to let the moisture coming through the concrete evaporate. It does make you wonder how well this actually works? It seems to be working on my floor after 3 years, but only time will tell. My old concrete floor had tile pavers on it and when I pulled up the tiles, there was an odor and a very small amount of mold, so I knew I had a least a slight water problem. So far, the odor has not returned with my new sub floor and engineered wood flooring. There are ways to test a concrete floor for moisture. My floor passed the simple plastic sheet test, but I would encourage anyone thinking about putting wood over an old concrete slab on grade to test before spending all the money and labor involved. Here is a good article on the subject. www.sspc.org/learning_center/concrete-moisture-testing-why-it-matters/#:~:text=ASTM%20D4263%20%E2%80%93%20Indicating%20Moisture%20in,the%20concrete%20indicates%20excessive%20moisture.
We are building a house on a concrete slab and stained it. It looks beautiful. We will wear shoes and do not plan to stand on it for hours. In summer when it is hot and humid I may take my shoes off. I will not have to worry about what may be “growing” under all that stuff that is being put on top of this slab.
I've used this product for a below-grade walk-in cooler with a concrete floor. Cooler temperature set at 35 degrees. With an uninsulated floor, you will never pull the heat out of it. You need something to break that heat path, and this works perfectly. 1.5" topped with pressure treated plywood with Dri-Dek on top (red, just to be pretty). I highly recommend this product.
I did the same in my 40 foot shipping crate. With 12 inches in the ceiling 8 inches in the walls. On larger jobs I now have a heated portable shop for my builds. Great for the northern cold winters. P.S great on the knees.
We've done similar install. Instead of 3/4 advantect , we use 2 layers of 1/2 OSB with heavy plastic sheeting underneath ( if over concrete). You must leave a 1/4 gap between sheets or it will expand and buckle. Then use 1.5" staples instead of standard 2" staples so you don't penetrate the underside of the plywood ( hitting your foam or concrete below) Glue and screws between plywood is unnecessary. Instead, install a layer of Fortifiber aquabar vapor barrier. Then you have extra moisture protection. installed 11000sf this way in 2011. it works.
I did this in a garage to extra room conversion with one layer of 3/4 OSB flooring plywood. I used cement screws to really keep it flat to the slab. no need for 2 layers of plywood.
Our house is a DELTEC. We built the foundation with Logix ICF's and put 2" of 20 PSI foam under the floor. There is one point load bearing the floor load for the entire house. It sits on a 4x4x12 footing. That's the only place where there is. a thermal connection to the ground. I am in a northern climate and our Subsoil temperatures are probably in the 40's. I know that my well water is around 45 degrees. We do have in floor heat in the basement.
Cool that you included footage of the concrete removal for the P-Trap. Just a couple of points. Concrete dust is very toxic and will mess you up over time. It can contain large amounts of heavy metals from the fly ash and the silicon particles can cause silicosis. Although the guy had a water backpack to feed his saw, I think he forgot to turn the valve on or did not have enough flow to bring the dust cloud down sufficiently. Also the neck gatter does pretty much nothing for protecting him. He should be wearing a rubber sealing Half face respirator with N-95 filters at a minimum. Speaking from experience, it makes me sad to see people hurt themselves with air-borne toxins of any kind.
We have a 1939 house in Ohio with 2 bedrooms on a slab. I remodeled one last year and I did the floor with Dricore + and then a layer of plywood on top of that and then hardwood. While the insulation on the dricore isn't huge, it made a huge difference in the comfort of the floor. We had carpet before and it was always ice cold in the winter. Now you can walk on it barefoot in the winter and it just feels cool. I can imagine a floor like this would be pretty comfy in the winter there or here. I will be doing the other bedroom this year with the same method I would like to go thicker like Matt shows but we don't have the ceiling height to lose to go that thick.
The floating subfloor also helps prevent damage to some types of flooring from seasonal shifting of the slab. If the slab is already not level, depending upon the severity of the foundation wonkiness you might want to stabilize the foundation - which has a lot to do with site drainage.
"Deflection" in the floor. I love this, because I hate standing on my slab floor and its coldness, and have been trying to brainstorm ways to add deflection for comfort in future upgrade of floor covering.
@@takehikes it's nice to see different materials living in Long Island New York I do 99 percent residential I seen people do heated floors in there kitchens, bathrooms but I've never used or seen the tape before. 👍🇺🇸🇺🇸🇺🇸🇺🇸
You need to talk to your guys about the spacing. As a flooring contractor of 34 years, I can tell you with complete confidence that the subfloor and flooring are going to expand and contract more than your 1/4 inch gap will allow. There is a reason that the flooring manufacturers require more than that for spacing. And yes, I have replaced several floors that failed because of inadequate spacing. Of course non of them were originally installed by me. But that is not to say that others haven't had that pleasure. I really have no way of knowing. But I do know that 1/4 inch is not enough.
I'd like to see some discussion of whether the second layer should be perpendicular. The weakest joint is the butt ends. A perpendicular layer means there will be a butt end on top of a butt end joint. If they are all the same direction(which is the standard recommendation for tile installs over joist) the weakest point is likely much stronger.
I know a carpenter from north Carolina. He uses the sleeper system you described - but cuts the 2x4's in half and lasts insulation between the sleepers before installing the flooring.
Interesting detail. My thoughts: 1) I live in Austin, same as you. If you blink, you miss winter. So, return on investment isn't nearly as high as with, say, an FPSF home in the north. So, yeah...the homeowner will benefit from this on the 20 days it freezes in Austin per year. 2) Besides the financial costs you outlined, there's a 3" reduction in ceiling height, or you're building the structure 3" higher, which translates to even more construction costs. Finally, 3) flex/comfort in the floor. You're absolutely right about concrete being unforgiving on the feet and knees. But not too many homeowners have/want concrete floors. Hardwoods on top of glue on top of slab...that's already softening up the floor a bit. So, I don't know. I'm a little skeptical on this detail, particularly in this climate. I just don't see the ROI.
@@timrich6755 Matt doesn't have financial ROU here, the clients do. Matt has his time in but it is the clients money, not his.Well... its "his" now but the clients will have to live there decades to see the money back in utility cost savings.
slab insulation has been standard for over 40 years in Northern Europe... Mostly now we only use UNDER slab insulation, cause that makes most sense. Thickness for our climate is at minimum 300mm, often up to 500 mm (20 inches), we use EPS or XPS. Insulation is relatively cheap. No issues with moisture when capillary breaking layer is used (decades of experience here).
Most people don't understand the dynamics of PSI (pounds per square inch or pressure per square inch). Here's a few examples of the power of PSI: 1. A sail boat: just a slight breeze and the area (square inches) of sail are enough to move a big ship. 2. A large driveway gate that has privacy slats: when the wind blows, it will tear the gate off of the posts. 3. A water pipe that is conducting water at 80 psi, that ruptures underneath a concrete driveway or slab foundation: that pressure will lift the driveway or the slab until they break. Getting back to the boat analogy: they float by displacing weight....
17:06 "...around 40 bucks a sheet - ish, mas o menos..." For those of you who missed it, Matt just flexed his Spanglish language abilities. Sub-Titles was confused as well. lol!
Here in east/north europe people usually do a heated floor nowadays. It usually goes with simillar foam and a pvc pipe zigzagging to spread the heat evenly. So in vinter you have really comfy flooors
I like the Legalett system. It is a frost protected structural shallow foundation. They use foam under an 8" thick structural slab. Because of the thickness and reinforcement of the slab, you have no footers, the entire slab becomes the footer. You can have true 100% continuous insulation on the entire envelope of the home including underneath the foundation with no thermal brakes anywhere. This system can be beneficial in areas that are warm too, because it can be a solution to building on expansive soils.
Have you worked with foamglass yet, Matt? It's heat-expanded glass that turns into a sort of 'pumice stone' product, and comes as large lumps of gravel (40mm) and as a slab product. It's insulating but also structural. In this situation it's possible you could have built the loadbearing walls on top of a course of foamglass block. Definitely recommend checking it out, as the possibilities are almost endless. Unfortunately my last clients were too nervous to go for it, but I detailed out for a foamglass raft foundation - you run it about 650mm wider all round than the house footprint, and it then acts as structural foundation, damp course, and insulation, with the bonus of the 'french drain' effect around the perimeter too. You can then pour your slab and away you go, with no perimeter weak points of insulation / bridging etc. Another handy way around these old houses on concrete slabs that I've had a good result with is 'gluing' down expanded cork insulation boards with bituminous paint, then floating floor like you're doing here - very inexpensive way to improve the house.
I love his build methods. Yes more expensive to build, but for the long term you’ll come out ahead with the monthly utility costs being much lower than the minimum code builds these production builders are using.
My father and I did something similar on a slab foundation as prep for nail down engineering hardwood flooring. We used XPS and 1 layer for advantec. We would have loved to do 2 layers but we didn't plan for the insulation + hardwood build up and it raising the floor further would have caused issues with the entry door height (already installed). We also put down two coast of a roll down vapor barrier on the slab before the insulation board. We were more concerned about movement so we used tapcon screws to secure all the layers to the concrete. No we didn't seal those penetrations. Probably should have. Just as a note, just the vapor barrier made a huge difference in perceived humidity. This home is on the ocean in Maine. The slab was installed with gravel bed, plastic and 2 layers of blue board. It also has french drains. I don't think it was a problem of bulk water just normal humidity moving up through the concrete.
Just mind blown. Not about the insulation part though. In Finland we always pour gypsum or concrete screeds on top of insulation... but two sheets of osb etc. would be much more practical in many cases! Thanks Matt!
I’ve been working on the house that had insulation on concrete and it was day and night difference in heat, the only thing that was done wrong, concrete wasn’t sealed and was letting moisture from concrete under insulation, when we removed some parts for new project there was a lot of mold under that insulation. Sealing that concrete is important for the long run in my opinion.
I feel like this gives up the benefit of the thermal mass, that the comfort would be higher with the concrete on the conditioned side of the insulation.
Comfort in therms, yes, concrete is unforgiving. I put 4" blue board under concrete, and have on occasion run two layers of floating 5/8" U.L. on sill seal( 16"o.c.) to then add hardwood
This reminds me of a JLC article where they did a similar thing in a basement. Instead of doing a basement slab, they did a gravel base, followed by a sheet of EPS, and then two layers of Advantech. I think it was so they could install hardwoods in the basement without having to wait for the slab to release the excess moisture. Very cool idea, which I've thought about doing myself.
I’m in Ontario, instead of using those 2X2 OSB T&G sub flooring, I used that exterior dimpled foundationwrap on slab, then I could use foam insulation or put 4X8 T&G OSB for more stability than the 2X2.
In KS we do get the right humidity and temp. Sometimes a concrete floor will sweat. Sometimes for several days. I would think that could cause a problem with that insulation laying directly on the floor.
Some codes call for a water makeup system for infloor drains. So the Ptrap doesn't go dry from evaporation. Using mineral oil in the Ptrap is new to me and sounds like a good idea for an emergency drain!
ooooooh so close Matt! It may be the first in Texas, but I did this in North Carolina 6 or 7 yeas ago. I used 2" of foil faced polyiso and couldn't afford the Advantech, but the rest is essentially the same. I couldn't find a single mention of a similar system back then but really wanted to insulate my floor and add a moisture barrier for hardwood floors so it ticked all the boxes. I just toured the house 2 weeks ago and the floors still look brand new.
Love this detail. My only concern would be if you do manage to get water intrusion where does it go? I do commercial athletic hardwood floors and we see some what similar designs there but with an air gap underneath to account for moisture. Also we would put the second layer of plywood or in this case OSB at a 45 to even further reduce the chance of seams overlapping.
Hey Matt, I have a concrete back porch that was closed in. Just the thing for that room. Thank you, love the way you think! Would it also work on a crawlspace floor? Keep up the great videos.
Matt you really need to study up on PFAS and other toxic compounds commonly present in adhesives and waterproofing compounds and do a vid series on that. VOCs are only the start of things we don't want in our homes!
Hey Matt. Thanks for sharing the details of your top of slab insulation project. I’m considering doing something similar and just wanted to check back to see if you have any lessons learned from this experience and if you would use the same detail again? If not, why and what would you change? Thanks!
@@buildshow I would absolutely love to tour this home of yours when finished. With all the hours spent just watching the project, not even in my own homes have I been so curious. Needed or not, I’m glad you’re pushing the envelope and expanding minds. Super cool stuff. 👍
@@buildshow Agreed. I've got to where I have walking on concrete and prefer a wood floor with some cushion. If I ever have the luxury of building my own home, it will have a fully closed and insulated crawlspace. Wood is just far more comfortable than concrete.
It's usually done to grandfather in older houses that don't meet current zoning requirements for lot line setbacks or max square footage as a percentage of overall lot size. Sometimes in a renovation, it's cheaper to tear it down and rebuild than it is to try and fix existing problems.
legally a remodel. pretty common rule that as long as you leave the foundation, and lots of times a single original wall frame, no matter what else you do it's a remodel for legal/permitting purposes.
I live in TN and recently did something similar in my basement. As a foam manufacturing engineer, I already knew that EPS had the compression strength and built in vapor barrier needed to protect my subfloor. I went cheap though, only one layer of subfloor instead of 2. It's a rehab and not a new construction. 1" foam on the floor with 3/4 sub and 2" foam on walls with furring strips for drywall. Once the area was dehumidified its stayed constant 50% and temps hardly fluctuate.
I used to look forward to moving on to the 2nd floor of the buildings I was wiring, usually wood floors up there and it was noticeably nicer to walk on all day.
I was just about to say when it comes to an area that you're not going to be able to access later on you're better off going with the better materials because you definitely do not want to have to rip everything up. This flooring installation hopefully works great enough where hopefully it could replace heated flooring because you see so many people running packs to stop that cold weather from coming up through the concrete floor. Obviously heated flooring is better I'm just saying if you can cut out that cost and put normal heating through the house it will definitely cut down on your building cost.🇺🇸
I wonder if it would be possible to use ZIP R- sheathing as the first insulating base layer then just have one additional layer of advantech🤔🤔🤔 Would save on some of the labor since the insulation and first subfloor layer are integrated as one.
I considered that, but Huber will not warrant for that use. I was concerned about moisture coming up between joints and rotting the OSB. I think the graphite based insulation that has no food for mold will work much better, and also taping to walls and sealing joints should work well. It was learned with SIP's that alternating the direction of layers significantly helped on thermal bridging. As an ME PE, decoupling the floor reduces the overall HVAC load.
I can tell you about thermal bridging...I'm my current apartment, it's the worst I've ever felt. In the summer, the whole floors get progressively as warm as the exterior brick gets. In the winter, all the bottom of the walls and the floors from outside in get cold. I believe the floors are concrete or have concrete on top for "condo like soundproofing" I got told. So concrete directly couple to the exterior through the floor/wall junction. Insulation is lacking at the bottom of the walls, windows are double sliders, single panes, with aluminium frames, no insulation, I can poke the brick if I stick a long screwdriver behind the trim. Those windows suck, can't seal them properly, and even foaming around doesn't help the massive heatsink those alu frames are. Would have cost pennies to foam them from factory or on install.
Matt: All the comments about using a 10 mil poly barrier between the concrete floor and the foam seem to have merit by putting a true 100% moisture barrier even up the sides of your exterior walls (mastic?). I understand the foam may serve as a moisture barrier but there are breaks at each board junction. You solve that with tape. Installing the poly barrier would eliminate all the material, labor, concern and fuss with your system as well as protecting the bottom of the foam from the moisture travel from the ground through the concrete. Gotta think you and Steve B. thought this out, what am I missing? Thank you.
I think the point is to protect the floor system not just from the slab's moisture, but from moisture in the air (e.g. if the AC is busted for whatever reason) passing between the foam and condensing on the cool slab.
@@hailexiao2770 Got to about 9:15 on the video and listen to Matt explain why he is doing the floor the way he is. Please reread what I posted above to see my concerns about his technique. Good talk.
I have this problem too with clay soils in California. You can do three layers of plywood and stager the joints of course. I have used wood glue and staples for the plywood layers. I would used a dimpled barrier made for putting wood over concrete first. Osb is another option, but of course plywood is better.
@@tomruth9487 Thanks! I have also looked at the Schluter Ditra Membrane Tile underlayment and tile as an interesting option as well. I just wonder if there is a proven 'floating' method.
Awesome helpful video: Flooring question, is it safe to install 1/2" hardie backer board 3ftx5ft 38 lbs each over Plywood for the entire 2nd story floor about 3600 pounds total extra pounds for Texas home ? No issues for weight? Or etc
Well done. I think swapping the order of the thermal break to the inside makes a lot of sense in the south. The cooler, dryer conditioned air is on the inside. You could have warm vapor driving upwards from under the slab and now it has little chance to come in contact with a cold condensing surface. It's the "perfect wall" used in the north, reversed. In the north, during the heating season the warm heated moist air would move outward towards the siding where a cold surface would be there to meet it - leading to condensation and mold. The exterior insulation reduces that chance because that condensing surface is now warmed/isolated. It makes it less critical for air sealing details to hit the mark.
Brian, thinking about doing an on slab build in the north. So you think it makes more sense to insulate under and around the slab/footings (and then on up the outside of the walls. From a thermal break standpoint I agree. From an interior comfort standpoint, walking on the interior insulation sounds more appealing... I'm assuming doing an under slab with say 1/2 of foam on the inside might create moisture entrapment, even if it wasn't taped and small gaps were left.
@@ssoffshore5111 It really boils down to dewpoint in a wall. You'll want to consider putting as much on the outside as you can in relation to what's on the inside. The closer the dewpoint is to an interior surface, the more likely that surface will become wet and bring potential for mold. I don't think you can put insulation under a footing - check with a engineer. But you can put a thermal break all the way around the perimeter of your slab between the slab and the concrete wall (eg: 1.5" of rockwool or EPS rigid). When you insulate under your slab and you use a vapor barrier above the insulation to keep it from iceburging up through the concrete, that side of the assembly becomes vapor closed. So if you put anything on the interior side, consider making it vapor open so that it allow drying potential to the living space. Then in the living space your HVAC equipment can manage what little vapor/humidity that can result. So if you put an 1" of rigid on top of the slab for comfort, consider recycled EPS or Rockwool Comfortboard 80
Does Rockwool offer any under slab insulation. Seems like a good idea as it would be bug proof already termites are my concern. This may be another option but I was hoping to keep my concrete in the thermal envelope for its mass to help reduce fluctuations. Use it like a battery.
Matt, I have 1,000 square foot workshop that is slab on grade it is about a 6.5” step down from the first floor of the wrest of my house. We are wanting to finish this space so we were thinking to lay down some type of insulation/vapor barrier that we can then install floor joist overtop of to create an air gap where we can run plumbing, electrical and potentially HVAC. The goal would be to get the floor in the workshop to the same floor height as the wrest of the house. What would you recommend in terms of an insulation product and or just a general way to go about it. Thanks
Thanks for the video, do you need to make sure your floors are level before you put down the foam? Looking to put in new floors on cement slab not sure if my floor needs levelling.
It was not cheaper to pour a 3” reinforced slab with radiant heat on top of the insulation? You could acid-finish the slab & you were done. Customer preference? This is a question “a little it off topic”. You used “Ray Magic” panels on some of your projects & this is the best way to cool a house (I live in Georgia). I know that an energy recovery unit is necessary to provide fresh air & to maintain the humidity levels low & avoid condensation. For heating I am a strong believer in radiant floors. Where I can buy radiant cooling panels? Thank you, Harry.
If you are feeling the bounce then there is surely more play in that floor in terms of load. Not sure how i would feel about the compression after putting in cabinetry and stone counters. Interesting video all the same. Cheers Matt
Not sure on how he plans on dealing with it, but resilient channels would be a good option if he’s familiar with them. You could squeeze an extra half inch of insulation into the cavities then, on top of the improved STC rating you’d get in the walls from the channels (when detailed properly).
@@zakiducky there is no need for more insulation in that house. It already has insulated shearing, plus 2x6 exterior walls. Resilient channel would also be an odd choice where sound control is unlikely needed, IMO
Your crew acts professional as heck. If my guys heard me say I was "spreading my load out" then it would have been an eruption of one liners.
Your almost 50 and have more energy than this 33 year old!
Letting us know the costs is great for those of us that actually care about building a quality, comfortable, long lasting home. Ignore the people that say that's too much!
I have 15 years on you and I really appreciate the fact that this "upgrades" the concrete slab into something that is comfortable to stand on. Thank you!
When you started to talk about the foam with the overlay, the first thought that came into my head was pianos and gun safes. I laughed to myself when you mentioned it a few seconds later.
I’ve been watching each episode of the build show for a while, as a result my next house is going to be wicked awesome.
You probably won't be able to afford it.
Trust in Jesus Christ our Lord And Savior who forgives everything and heeds those who call upon Him, AMEN
And wicked expensive.
Matt has made a TH-cam channel basically all about insulation. And I freaking love it.
What?!?!?!
Sounds like a dream! What is the channel?
First, no elephants in the room! So you’ve got that going for you. And the intangible of comfort (and the craftsmanship and thought that goes into it) is worth so much more than the one time cost of producing it. Keep it up, Matt. I think it’s really compelling.
Mark Palmer, But you might have to think if you have a grand piano and point loading on the legs.
Trust in Jesus Christ
This guy sure knows a lot about spreading his loads around.
I insulated half of a shed using a similar idea on the floor, and it works, with some caveats. Lots of things I would do differently. And now this video takes what I learned with my shed and takes it up a notch or three. Cool. I'm building a house next summer, and this is how I'm going to do the floor. Thank you, Matt. Great channel.
Such as?
Matt always stretches my brain to think outside the box. His knowledge and connections benefit so many and make me feel like I’m not completely ignorant when it comes to Texas construction and beyond!!
Slab top insulation. Dang. Steve Baczek, you absolute mad man.
Ain't he great?
Man, I wish I had a business partner like this guy. While its nice on one hand to run a business without partnerships, when its someone that has the same love of construction methods, design, and quality then the overall finished product and long term client satisfaction is at a peak. We have developed a good reputation in our area with our clients. All of our work is 100% referrals, and even with the hurdles of 2020 we are still booked out for 8 months with multiple proposals still out.
*Thank you!* Excellent solution for a "barno" that does not have subfloor heating.
Actually they call it a "barndo" short for barndominium. I'm planning on building one when I retire to TX eventually.
can this method be used with radiant heating or would the insulation make it useless. can subfloor be put over radiant heated slab with a vapor barrier?
@@gm08351 in-slab radiant wouldn't be effective if you're insulating over top of slab as shown here. You could run radiant piping on top of the new subfloor assembly and it would be more effective than in-slab, since you're not wasting heat on the mass of the concrete... you could also obviously use the electric radiant grid floors that are becoming common.
Matt, Congraduations! You've won the KBBL contest and your prize is a full grown African elephant!
A way to save a lot of money that I did when building my house was I bought reclaimed foam boards and put them under the concrete. I put 4" of XPS foam under the slab (not the footings) but I did put a 4" XPS thermal break between the footing and the basement slab. I have also used the premade OSB subfloor system that goes on top of the slab. I live in Massachusetts and my basement stays so much warmer than any other basement I have been in here.
reclaimed polyiso is widely available and fairly inexpensive for its r value. Craigslist is where these companies advertise and many ship nationwide.
Closed cell sprayfoam with Cement on top is the ultimate. Bring the foam up along the interior walls. Total envelope
philip dias, How thick is the concrete over the foam? But then you still have a concrete floor that's hard on your knees?
@@tomruth9487 usually one or two inches over . You basically create a new floor that is thermally broken from the foundation. You build your internal qalls on the newslab.
@@Phil-D83 Interesting, thanks for the reply.
I really enjoy all of your videos. I can see your passion for innovative and logical construction styles that focuses the attention to detail. I am a Radon Expert and many of the components you use also help with reducing radon into a building. Thank you and again I really appreciate all your videos and always look forward to new ones. Keep up the good work!
Floored 8 years! Got beat up physically ! Tool and Die 23 yrs! Damn near fried brain!! Gbless sir awesome work!!!!!!!
Thanks for pointing out the necessity to get the higher PSI foam if i have an elephant in my house. I almost bought the 10 psi, but just in the nick of time I changed the order to the 16 psi.....its a baby elephant
I actually used this same technique for my new construction in Houston, TX. I skipped out on the insulation board due to cost and used an off-brand T&G OSB floor. I used a 6mil poly plastic as my moisture barrier against the concrete as well. Solid floor solution for sure and it is definitely softer on your feet overall. My main comment is that this is 4x the cost of a typical tar screed subfloor for solid wood floors. My main reason of doing this was to avoid the toxic chemicals used in typical subfloor design. I also used special low VOC glue to connect the floors together. Keep in mind my house if about 1900sqft of flooring.
I had to google "hot tar screed" Don't think we do that out here in California. Sounds like a good way to go.
Hi Lee we're building in Houston too. Can I DM you for more details on your approach?
@@utubesj, Yup that's fine.
We've been doing this in basements in Canada for years. Except there are manufactured panels 2'x2' osb with foam laminated to them. They've even gotten better and added air channels in the foam to reduce any moisture that could get trapped.
We have those here too in the us.
@@mitchdenner9743 Any product names or links you could share? Certainly sounds like an interesting option.
I've even seen a job done with the following layers in Toronto canada- 10 ml poly, then a dimple foundation wrap layer, then 2" soprema SOPRA-XPS 30, then 3/4" plywood, then flooring. I thought this was overkill.
Those are no good. They are a little expensive, provide very little insulation, and provide very little structural rigidity.
Are you talking the dimple layer or the rigid XPS foam board at 2 inches thickness.
I am planning on doing something similar to my basement up here in Canada. Only difference is I am putting down DMX 1-step, then foam then plywood. Glad to see I am not out to lunch with the idea of insulating on top of my slab.
I think you are smart to use the DMX or you can use Delta FL. I used the Delta and then 2 sheets of 1/2" osb with wood glue and stapled together. Plywood of course would be better. I glued my flooring down so osb seems to be working ok.
Check out this video th-cam.com/video/YRZmWEx3Vno/w-d-xo.html
@@saralola3171 Very good video, thanks. With laminating ( I used glue and staples) 2 sheets of 1/2" plywood or osb instead of one layer of t &g material, you can cut down or eliminate entirely having to screw the subfloor down or messing with tongue and groove problems. This is depending on how flat your concrete floor is. The whole new subfloor and new flooring can float and only be held down on the edges by the baseboard. Again this is if your concrete floor is flat enough to start with. A floor leveling material can be used over the concrete if necessary. The whole theory with a dimpled vapor barrier is to let the moisture coming through the concrete evaporate. It does make you wonder how well this actually works? It seems to be working on my floor after 3 years, but only time will tell. My old concrete floor had tile pavers on it and when I pulled up the tiles, there was an odor and a very small amount of mold, so I knew I had a least a slight water problem. So far, the odor has not returned with my new sub floor and engineered wood flooring. There are ways to test a concrete floor for moisture. My floor passed the simple plastic sheet test, but I would encourage anyone thinking about putting wood over an old concrete slab on grade to test before spending all the money and labor involved. Here is a good article on the subject.
www.sspc.org/learning_center/concrete-moisture-testing-why-it-matters/#:~:text=ASTM%20D4263%20%E2%80%93%20Indicating%20Moisture%20in,the%20concrete%20indicates%20excessive%20moisture.
We are building a house on a concrete slab and stained it. It looks beautiful. We will wear shoes and do not plan to stand on it for hours. In summer when it is hot and humid I may take my shoes off. I will not have to worry about what may be “growing” under all that stuff that is being put on top of this slab.
You bring up a good point.
@@tomruth9487 just think about how much extra material is wasted too.
Just be careful, cold floors are not great for your circulation and kidneys!
I've used this product for a below-grade walk-in cooler with a concrete floor. Cooler temperature set at 35 degrees. With an uninsulated floor, you will never pull the heat out of it. You need something to break that heat path, and this works perfectly. 1.5" topped with pressure treated plywood with Dri-Dek on top (red, just to be pretty). I highly recommend this product.
I did the same in my 40 foot shipping crate. With 12 inches in the ceiling 8 inches in the walls. On larger jobs I now have a heated portable shop for my builds. Great for the northern cold winters. P.S great on the knees.
We've done similar install. Instead of 3/4 advantect , we use 2 layers of 1/2 OSB with heavy plastic sheeting underneath ( if over concrete). You must leave a 1/4 gap between sheets or it will expand and buckle. Then use 1.5" staples instead of standard 2" staples so you don't penetrate the underside of the plywood ( hitting your foam or concrete below) Glue and screws between plywood is unnecessary. Instead, install a layer of Fortifiber aquabar vapor barrier. Then you have extra moisture protection.
installed 11000sf this way in 2011. it works.
I did this in a garage to extra room conversion with one layer of 3/4 OSB flooring plywood. I used cement screws to really keep it flat to the slab. no need for 2 layers of plywood.
So your garage is an energy pig with a unforgiving floor?
@@njsification the floors are warm now. so you are a clueless keyboard warrior?
And who said anything about plywood. Advantec is 3/4 OSB. Talk about clueless keyboard warriors
Our house is a DELTEC. We built the foundation with Logix ICF's and put 2" of 20 PSI foam under the floor. There is one point load bearing the floor load for the entire house. It sits on a 4x4x12 footing. That's the only place where there is. a thermal connection to the ground. I am in a northern climate and our Subsoil temperatures are probably in the 40's. I know that my well water is around 45 degrees. We do have in floor heat in the basement.
Cool that you included footage of the concrete removal for the P-Trap. Just a couple of points. Concrete dust is very toxic and will mess you up over time. It can contain large amounts of heavy metals from the fly ash and the silicon particles can cause silicosis. Although the guy had a water backpack to feed his saw, I think he forgot to turn the valve on or did not have enough flow to bring the dust cloud down sufficiently. Also the neck gatter does pretty much nothing for protecting him. He should be wearing a rubber sealing Half face respirator with N-95 filters at a minimum. Speaking from experience, it makes me sad to see people hurt themselves with air-borne toxins of any kind.
We have a 1939 house in Ohio with 2 bedrooms on a slab. I remodeled one last year and I did the floor with Dricore + and then a layer of plywood on top of that and then hardwood. While the insulation on the dricore isn't huge, it made a huge difference in the comfort of the floor. We had carpet before and it was always ice cold in the winter. Now you can walk on it barefoot in the winter and it just feels cool. I can imagine a floor like this would be pretty comfy in the winter there or here. I will be doing the other bedroom this year with the same method I would like to go thicker like Matt shows but we don't have the ceiling height to lose to go that thick.
Very smart, slabs radiate everything from the earth right up through your feet.
The floating subfloor also helps prevent damage to some types of flooring from seasonal shifting of the slab. If the slab is already not level, depending upon the severity of the foundation wonkiness you might want to stabilize the foundation - which has a lot to do with site drainage.
"Deflection" in the floor.
I love this, because I hate standing on my slab floor and its coldness, and have been trying to brainstorm ways to add deflection for comfort in future upgrade of floor covering.
That 'comfort of “give “ under foot' in my house is so great I can hear people walk, squeak, squeak, -- Great presentation, good info
Videos like this are so great just to see products you've never used before or I've never seen this product but see how well it works 👍🇺🇸
Done often in the radiant heating world on existing slabs.
@@takehikes it's nice to see different materials living in Long Island New York I do 99 percent residential I seen people do heated floors in there kitchens, bathrooms but I've never used or seen the tape before. 👍🇺🇸🇺🇸🇺🇸🇺🇸
You need to talk to your guys about the spacing. As a flooring contractor of 34 years, I can tell you with complete confidence that the subfloor and flooring are going to expand and contract more than your 1/4 inch gap will allow. There is a reason that the flooring manufacturers require more than that for spacing. And yes, I have replaced several floors that failed because of inadequate spacing. Of course non of them were originally installed by me. But that is not to say that others haven't had that pleasure. I really have no way of knowing. But I do know that 1/4 inch is not enough.
Great job. We enjoy your work on these tips.
I'd like to see some discussion of whether the second layer should be perpendicular. The weakest joint is the butt ends. A perpendicular layer means there will be a butt end on top of a butt end joint. If they are all the same direction(which is the standard recommendation for tile installs over joist) the weakest point is likely much stronger.
Matt, great information. On the Build Show
I know a carpenter from north Carolina. He uses the sleeper system you described - but cuts the 2x4's in half and lasts insulation between the sleepers before installing the flooring.
Thanks for sharing! We've loved watching this project unfold!
Interesting detail. My thoughts: 1) I live in Austin, same as you. If you blink, you miss winter. So, return on investment isn't nearly as high as with, say, an FPSF home in the north. So, yeah...the homeowner will benefit from this on the 20 days it freezes in Austin per year. 2) Besides the financial costs you outlined, there's a 3" reduction in ceiling height, or you're building the structure 3" higher, which translates to even more construction costs. Finally, 3) flex/comfort in the floor. You're absolutely right about concrete being unforgiving on the feet and knees. But not too many homeowners have/want concrete floors. Hardwoods on top of glue on top of slab...that's already softening up the floor a bit. So, I don't know. I'm a little skeptical on this detail, particularly in this climate. I just don't see the ROI.
You forgot the TH-cam benefits and the build network benefits. 🙂
@@timrich6755 Matt doesn't have financial ROU here, the clients do. Matt has his time in but it is the clients money, not his.Well... its "his" now but the clients will have to live there decades to see the money back in utility cost savings.
slab insulation has been standard for over 40 years in Northern Europe... Mostly now we only use UNDER slab insulation, cause that makes most sense. Thickness for our climate is at minimum 300mm, often up to 500 mm (20 inches), we use EPS or XPS. Insulation is relatively cheap. No issues with moisture when capillary breaking layer is used (decades of experience here).
What is capillary breaking layer? Can you give more details about this method?
Most people don't understand the dynamics of PSI (pounds per square inch or pressure per square inch). Here's a few examples of the power of PSI: 1. A sail boat: just a slight breeze and the area (square inches) of sail are enough to move a big ship. 2. A large driveway gate that has privacy slats: when the wind blows, it will tear the gate off of the posts. 3. A water pipe that is conducting water at 80 psi, that ruptures underneath a concrete driveway or slab foundation: that pressure will lift the driveway or the slab until they break. Getting back to the boat analogy: they float by displacing weight....
Thank you Matt, really appreciate the level of details you provide in your videos
17:06 "...around 40 bucks a sheet - ish, mas o menos..." For those of you who missed it, Matt just flexed his Spanglish language abilities. Sub-Titles was confused as well. lol!
Here in east/north europe people usually do a heated floor nowadays. It usually goes with simillar foam and a pvc pipe zigzagging to spread the heat evenly. So in vinter you have really comfy flooors
Great idea. Must plan ahead to install these products.
Good point ! Great idea ! It's time has come.
I like the Legalett system. It is a frost protected structural shallow foundation. They use foam under an 8" thick structural slab. Because of the thickness and reinforcement of the slab, you have no footers, the entire slab becomes the footer. You can have true 100% continuous insulation on the entire envelope of the home including underneath the foundation with no thermal brakes anywhere. This system can be beneficial in areas that are warm too, because it can be a solution to building on expansive soils.
Have you worked with foamglass yet, Matt? It's heat-expanded glass that turns into a sort of 'pumice stone' product, and comes as large lumps of gravel (40mm) and as a slab product. It's insulating but also structural. In this situation it's possible you could have built the loadbearing walls on top of a course of foamglass block. Definitely recommend checking it out, as the possibilities are almost endless. Unfortunately my last clients were too nervous to go for it, but I detailed out for a foamglass raft foundation - you run it about 650mm wider all round than the house footprint, and it then acts as structural foundation, damp course, and insulation, with the bonus of the 'french drain' effect around the perimeter too. You can then pour your slab and away you go, with no perimeter weak points of insulation / bridging etc. Another handy way around these old houses on concrete slabs that I've had a good result with is 'gluing' down expanded cork insulation boards with bituminous paint, then floating floor like you're doing here - very inexpensive way to improve the house.
I love his build methods. Yes more expensive to build, but for the long term you’ll come out ahead with the monthly utility costs being much lower than the minimum code builds these production builders are using.
The payback must be wayyy down the line. This is why "comfort" is the only sales pitch.
My father and I did something similar on a slab foundation as prep for nail down engineering hardwood flooring. We used XPS and 1 layer for advantec. We would have loved to do 2 layers but we didn't plan for the insulation + hardwood build up and it raising the floor further would have caused issues with the entry door height (already installed). We also put down two coast of a roll down vapor barrier on the slab before the insulation board. We were more concerned about movement so we used tapcon screws to secure all the layers to the concrete. No we didn't seal those penetrations. Probably should have.
Just as a note, just the vapor barrier made a huge difference in perceived humidity. This home is on the ocean in Maine. The slab was installed with gravel bed, plastic and 2 layers of blue board. It also has french drains. I don't think it was a problem of bulk water just normal humidity moving up through the concrete.
Incredible detailed and I find your attention to detail enviable but probably a budget buster on a standard or conventional remodel.
Keep spreading your load out.
Just mind blown. Not about the insulation part though. In Finland we always pour gypsum or concrete screeds on top of insulation... but two sheets of osb etc. would be much more practical in many cases! Thanks Matt!
You could have in-screed radiant heating in that screed and the insulation means it'd be heating the house and not the slab!
@@calmeilles True, but there is also alot of cases where in floor heating is not used.
I’ve been working on the house that had insulation on concrete and it was day and night difference in heat, the only thing that was done wrong, concrete wasn’t sealed and was letting moisture from concrete under insulation, when we removed some parts for new project there was a lot of mold under that insulation. Sealing that concrete is important for the long run in my opinion.
Yah lets hope Matt doesn't have any moisture wicking up to the insulation.
Definitely worth spending more on building a house. Interesting to see your build methods across the pond
What is the method where you are from?
in like it, good retro fit option, more typical thermal envelope occurs with ridged insul on inside face of frost wall.
I feel like this gives up the benefit of the thermal mass, that the comfort would be higher with the concrete on the conditioned side of the insulation.
Comfort in therms, yes, concrete is unforgiving.
I put 4" blue board under concrete, and have on occasion run two layers of floating 5/8" U.L. on sill seal( 16"o.c.) to then add hardwood
This reminds me of a JLC article where they did a similar thing in a basement. Instead of doing a basement slab, they did a gravel base, followed by a sheet of EPS, and then two layers of Advantech. I think it was so they could install hardwoods in the basement without having to wait for the slab to release the excess moisture.
Very cool idea, which I've thought about doing myself.
I’m in Ontario, instead of using those 2X2 OSB T&G sub flooring, I used that exterior dimpled foundationwrap on slab, then I could use foam insulation or put 4X8 T&G OSB for more stability than the 2X2.
Love this! Better than putting in a manifold-tubular heating system.
It’s not meant to replace your main heating system it’s meant to better insulate the slab or floor.
In KS we do get the right humidity and temp. Sometimes a concrete floor will sweat. Sometimes for several days.
I would think that could cause a problem with that insulation laying directly on the floor.
Some codes call for a water makeup system for infloor drains. So the Ptrap doesn't go dry from evaporation. Using mineral oil in the Ptrap is new to me and sounds like a good idea for an emergency drain!
ooooooh so close Matt! It may be the first in Texas, but I did this in North Carolina 6 or 7 yeas ago. I used 2" of foil faced polyiso and couldn't afford the Advantech, but the rest is essentially the same. I couldn't find a single mention of a similar system back then but really wanted to insulate my floor and add a moisture barrier for hardwood floors so it ticked all the boxes. I just toured the house 2 weeks ago and the floors still look brand new.
Love this detail. My only concern would be if you do manage to get water intrusion where does it go? I do commercial athletic hardwood floors and we see some what similar designs there but with an air gap underneath to account for moisture. Also we would put the second layer of plywood or in this case OSB at a 45 to even further reduce the chance of seams overlapping.
Christian Hayden. And I'm sure you know how maple loves to cup if given some moisture.
@@tomruth9487 most certainly!
Comfort is king for me!
Hey Matt, I have a concrete back porch that was closed in. Just the thing for that room. Thank you, love the way you think! Would it also work on a crawlspace floor? Keep up the great videos.
Always a good show on..... The Build Show"
Matt you really need to study up on PFAS and other toxic compounds commonly present in adhesives and waterproofing compounds and do a vid series on that. VOCs are only the start of things we don't want in our homes!
Great Vlog, I been waiting to see this kind of late Slab Top insulation..
Hey Matt. Thanks for sharing the details of your top of slab insulation project. I’m considering doing something similar and just wanted to check back to see if you have any lessons learned from this experience and if you would use the same detail again? If not, why and what would you change? Thanks!
Awesome. And elephants are awesome too.
How cold does it get there in the winter?
I could only imagine in the south you’d want the concrete to help conduct heat into the earth in the summer.
It’s mainly for loss in the winter but I think the year round comfort of “give “ under foot will be the best feature
@@buildshow I would absolutely love to tour this home of yours when finished. With all the hours spent just watching the project, not even in my own homes have I been so curious. Needed or not, I’m glad you’re pushing the envelope and expanding minds. Super cool stuff. 👍
@@buildshow Agreed. I've got to where I have walking on concrete and prefer a wood floor with some cushion. If I ever have the luxury of building my own home, it will have a fully closed and insulated crawlspace. Wood is just far more comfortable than concrete.
I refuse to accept that putting an entirely new house on an existing slab can possibly be considered a "remodel"
Its the Austin loophole. There used to be many teardowns which caused older residents to complain that the neighborhoods were being replaced
It's usually done to grandfather in older houses that don't meet current zoning requirements for lot line setbacks or max square footage as a percentage of overall lot size. Sometimes in a renovation, it's cheaper to tear it down and rebuild than it is to try and fix existing problems.
legally a remodel. pretty common rule that as long as you leave the foundation, and lots of times a single original wall frame, no matter what else you do it's a remodel for legal/permitting purposes.
Just need 3 "standing walls" in most of Texas I believe.
@@bwillan
Where I live you have to rebuild 1 wall at a time. If you tear down all the structure you have to rebuild to new code
I live in TN and recently did something similar in my basement. As a foam manufacturing engineer, I already knew that EPS had the compression strength and built in vapor barrier needed to protect my subfloor. I went cheap though, only one layer of subfloor instead of 2. It's a rehab and not a new construction. 1" foam on the floor with 3/4 sub and 2" foam on walls with furring strips for drywall. Once the area was dehumidified its stayed constant 50% and temps hardly fluctuate.
good comment; may I ask what brand foam did you use?
Any moisture barrier?
I used to look forward to moving on to the 2nd floor of the buildings I was wiring, usually wood floors up there and it was noticeably nicer to walk on all day.
I was thinking of doing this and running my plumbing under the subfloor, in the 2" foam.
I was just about to say when it comes to an area that you're not going to be able to access later on you're better off going with the better materials because you definitely do not want to have to rip everything up. This flooring installation hopefully works great enough where hopefully it could replace heated flooring because you see so many people running packs to stop that cold weather from coming up through the concrete floor. Obviously heated flooring is better I'm just saying if you can cut out that cost and put normal heating through the house it will definitely cut down on your building cost.🇺🇸
I wonder if it would be possible to use ZIP R- sheathing as the first insulating base layer then just have one additional layer of advantech🤔🤔🤔 Would save on some of the labor since the insulation and first subfloor layer are integrated as one.
I considered that, but Huber will not warrant for that use. I was concerned about moisture coming up between joints and rotting the OSB. I think the graphite based insulation that has no food for mold will work much better, and also taping to walls and sealing joints should work well. It was learned with SIP's that alternating the direction of layers significantly helped on thermal bridging. As an ME PE, decoupling the floor reduces the overall HVAC load.
Very informative and nicely designed.
I can tell you about thermal bridging...I'm my current apartment, it's the worst I've ever felt. In the summer, the whole floors get progressively as warm as the exterior brick gets. In the winter, all the bottom of the walls and the floors from outside in get cold. I believe the floors are concrete or have concrete on top for "condo like soundproofing" I got told. So concrete directly couple to the exterior through the floor/wall junction.
Insulation is lacking at the bottom of the walls, windows are double sliders, single panes, with aluminium frames, no insulation, I can poke the brick if I stick a long screwdriver behind the trim.
Those windows suck, can't seal them properly, and even foaming around doesn't help the massive heatsink those alu frames are. Would have cost pennies to foam them from factory or on install.
Matt: All the comments about using a 10 mil poly barrier between the concrete floor and the foam seem to have merit by putting a true 100% moisture barrier even up the sides of your exterior walls (mastic?). I understand the foam may serve as a moisture barrier but there are breaks at each board junction. You solve that with tape. Installing the poly barrier would eliminate all the material, labor, concern and fuss with your system as well as protecting the bottom of the foam from the moisture travel from the ground through the concrete. Gotta think you and Steve B. thought this out, what am I missing? Thank you.
I think the point is to protect the floor system not just from the slab's moisture, but from moisture in the air (e.g. if the AC is busted for whatever reason) passing between the foam and condensing on the cool slab.
@@hailexiao2770 Got to about 9:15 on the video and listen to Matt explain why he is doing the floor the way he is. Please reread what I posted above to see my concerns about his technique. Good talk.
Thank you Matt!
Any thoughts on how this flooring would handle a slab that moves a bit? Thinking the homes built in San Antonio.
I have this problem too with clay soils in California. You can do three layers of plywood and stager the joints of course. I have used wood glue and staples for the plywood layers. I would used a dimpled barrier made for putting wood over concrete first. Osb is another option, but of course plywood is better.
@@tomruth9487 Thanks! I have also looked at the Schluter Ditra Membrane Tile underlayment and tile as an interesting option as well. I just wonder if there is a proven 'floating' method.
Awesome helpful video:
Flooring question, is it safe to install 1/2" hardie backer board 3ftx5ft 38 lbs each over Plywood for the entire 2nd story floor about 3600 pounds total extra pounds for Texas home ? No issues for weight? Or etc
Well done. I think swapping the order of the thermal break to the inside makes a lot of sense in the south. The cooler, dryer conditioned air is on the inside. You could have warm vapor driving upwards from under the slab and now it has little chance to come in contact with a cold condensing surface. It's the "perfect wall" used in the north, reversed. In the north, during the heating season the warm heated moist air would move outward towards the siding where a cold surface would be there to meet it - leading to condensation and mold. The exterior insulation reduces that chance because that condensing surface is now warmed/isolated. It makes it less critical for air sealing details to hit the mark.
Brian, thinking about doing an on slab build in the north. So you think it makes more sense to insulate under and around the slab/footings (and then on up the outside of the walls. From a thermal break standpoint I agree. From an interior comfort standpoint, walking on the interior insulation sounds more appealing... I'm assuming doing an under slab with say 1/2 of foam on the inside might create moisture entrapment, even if it wasn't taped and small gaps were left.
@@ssoffshore5111 It really boils down to dewpoint in a wall. You'll want to consider putting as much on the outside as you can in relation to what's on the inside. The closer the dewpoint is to an interior surface, the more likely that surface will become wet and bring potential for mold. I don't think you can put insulation under a footing - check with a engineer. But you can put a thermal break all the way around the perimeter of your slab between the slab and the concrete wall (eg: 1.5" of rockwool or EPS rigid). When you insulate under your slab and you use a vapor barrier above the insulation to keep it from iceburging up through the concrete, that side of the assembly becomes vapor closed. So if you put anything on the interior side, consider making it vapor open so that it allow drying potential to the living space. Then in the living space your HVAC equipment can manage what little vapor/humidity that can result. So if you put an 1" of rigid on top of the slab for comfort, consider recycled EPS or Rockwool Comfortboard 80
@@MrBrianDuga Thank you!
Would there be any benefit to this vs. 4+ inches of eps under the slab before the pour? I feel like this looks ridiculously expensive in comparison...
Zoning laws. Keeping the original footprint avoids many laws related to sqft/parking/whatever other insane laws Austin has.
here in Louisiana it got down in the 30s last week or so.
My tile floor felt like a freezer removing all the heat from
the room
How many folks say, "ON THE BUILD SHOW!" at the end of these episodes? LOL
i say it with Matt in the beginning. only in my mind though.
🤣 it is catchy
Trust in Jesus Christ
Does Rockwool offer any under slab insulation. Seems like a good idea as it would be bug proof already termites are my concern. This may be another option but I was hoping to keep my concrete in the thermal envelope for its mass to help reduce fluctuations. Use it like a battery.
Matt, I have 1,000 square foot workshop that is slab on grade it is about a 6.5” step down from the first floor of the wrest of my house. We are wanting to finish this space so we were thinking to lay down some type of insulation/vapor barrier that we can then install floor joist overtop of to create an air gap where we can run plumbing, electrical and potentially HVAC. The goal would be to get the floor in the workshop to the same floor height as the wrest of the house. What would you recommend in terms of an insulation product and or just a general way to go about it. Thanks
touching the ground with your feet and feeling something is the definition of tangible btw
Thanks for the video, do you need to make sure your floors are level before you put down the foam? Looking to put in new floors on cement slab not sure if my floor needs levelling.
I love your videos. It seems to be only for the VERY VERY RICH
It was not cheaper to pour a 3” reinforced slab with radiant heat on top of the insulation? You could acid-finish the slab & you were done. Customer preference?
This is a question “a little it off topic”. You used “Ray Magic” panels on some of your projects & this is the best way to cool a house (I live in Georgia). I know that an energy recovery unit is necessary to provide fresh air & to maintain the humidity levels low & avoid condensation. For heating I am a strong believer in radiant floors.
Where I can buy radiant cooling panels?
Thank you,
Harry.
i like the idea of the poured craw space better then the slab subfloor
If you are feeling the bounce then there is surely more play in that floor in terms of load. Not sure how i would feel about the compression after putting in cabinetry and stone counters. Interesting video all the same. Cheers Matt
How do you deal with backing for your drywall at the base of the wall?
Blocking i guess.
Not sure on how he plans on dealing with it, but resilient channels would be a good option if he’s familiar with them. You could squeeze an extra half inch of insulation into the cavities then, on top of the improved STC rating you’d get in the walls from the channels (when detailed properly).
@@zakiducky there is no need for more insulation in that house. It already has insulated shearing, plus 2x6 exterior walls. Resilient channel would also be an odd choice where sound control is unlikely needed, IMO
probably a double floor plate.
@@kenbrown2808 that's not enough. 1.5" insulation plus 2x0.75 Advantech is 3", which is the thickness of a double plate