I got more out of this one video than I did from dozens and dozens of other videos. The price breaks are fantastic! You just saved me days of work. Please do more.
I have 3 crews doing 3 places right now and was thinking of doing this. I’m not doing it. Not for these. I’ll wait for a halo project and up my game in efficiency. But, damn if that wasn’t the most informative video I’ve seen on double studding. I’ve watched a bunch of videos that were much longer and did not give the details that I needed to feel confident enough to try it without the moisture issues that pop up in every other video on this subject. It’s like these builders wanna ACT like they’re showing you how to do a new and awesome technique, while at the same time, withholding those details that complete the picture. Then, they do a commercial. Great video. Very informative and eye opening. THANKS!
@@ASIRIDesigns Very good presentation. I built with double stud walls spaced 4.5" apart for R-44 insulation. Did not spring for the triple pane windows so that is my weak point but with 9.9kW solar array my house generates more energy than it uses each year- with enough extra to power two EVs. The double stud walls do help a lot with noise and since I built them myself the extra cost was not all that bad in 2014. Lumber has gone up a lot since then. Really any competent framing crew should be able to build double-stud and watching this video will educate them on how to install the windows. Thanks for providing the numbers also. One thing people should think about is the long term cost of poor insulation- it is so nice to never have any electric bill.
I could be wrong, since there are so many different materials involved, but I think the double wall system also allows for more acoustic insulation. That may be a consideration for some people, particularly in an urban or busy suburban area.
The stud is the main transmission of sound vibration from side to the other. When the two sides of the wall aren't connected to the same stud, sound is dramatically reduced. Interior walls can use staggered studs, where they are alternately moved a half inch off center from the previous stud. You would need stronger wall material to span twice the distance or put the studs more frequent, like 12 or 8 inches apart.
@@redneckcoder Both contribute, and the dampening effect of insulation helps a lot, but wood is a far greater conductor of sound than air. That's not my opinion. There's charts you can refer to with real measurements of many materials. Having wallboard connected to the stud makes it move together as one, whereas sound hitting between the studs has to transfer from air to board to air to board and then to air again, each time losing energy.
Great stuff as always. Double walls also provide a huge reduction in sound transmission for those in noisy neighborhoods. If maximum thermal efficiency is the goal, then double walls are practically impossible to beat. However... the labor costs are a HUGE factor here. The cost to install exterior EPS/XPS will be drastically cheaper than having a crew frame out double walls and the extra details for fenestrations. And for most areas of the country, the difference between R40 (R21 cavity + 4" of rigid foam) and R60 might not even be noticeable. You'd probably be better off putting that extra money into upgraded windows and doors. Building double walls with double-pane windows would be pretty pointless, for example.
@@DeuceDeuceBravo I would consider double walls just for the superior sound proofing alone. However, the configurations is different because you ideally want an air gap between each wall.
You know what I would love to see you do? A similar video on the all-out best wall assembly you can imagine, disregarding budget. Joe Lstiburek has a brief mention of the "institutional wall" but really doesn't go into details. I'm curious what something like that would look like. Basically infinite budget, but using actual building materials (no stuffing theoretical aerogel in the wall or something like that).
@@mindtrap0289 Interesting, could you explain more? I'm not a builder or structural engineer or anything, but just curious. I tried googling "p perfect block" and "perfect block wall" and nothing specific really came up.
I would love a video on leaving rafters exposed and insulating outside of the roof. We haven't figured out best way or a way we like yet. Being able to leave rafters exposed with roof board saves finishing money.
In Germany there is a type of wood based insulation popular that you can install onto the rafters. (Steico Dry) It is so stable that you can walk on the temporary wall and is weather proof for a couple of weeks until the finished roof is installed. As a bonus: If you use these wood based insulations you can build you roof without a vapour barrier because it is permeable and capillary active so that condesing water is transported to the warmer (and dryer) side of the insulation. Steico offers details for timber framed buildings on their website, the roof is basically from the inside to the outside: Rafters, Insulation (Steico Dry), sarking membrane (for weather proofing), roof battens, some sort of roof tiles. It is a more expensive type of insulation but you can renovate your roof completely from the outside and keep your rooms as they are without having to worry about the correct vapour barrier.
If I was building again, I would consider the double frame walls. But you would have to know that the work crews really understood the project and what detail has to be taken to achieve the correct level of efficiency. This would be a nightmare if corners were cut and later down the road, you came up with all your walls were filled with mold! Love the idea, but a lot of workers seem to be lacking in their effort to a proper job!
Well done! I built in1986 , staggered 2x4 stud walls 5” apart with 2 r19 fiberglass batts. 1 disadvantage is if or when mice get into the wall cavity they can travel freely. Otherwise I would do it again!
I’m planning a house now and mice are a huge problem here. I’m trying to decide between doing exactly what you did, or just sticking with 2x6 walls. This video also advocates for a gap behind siding, which is another runway for mice. Any other issues with your staggered wall.?
I'm totally sold on the double wall design. At the cost is daunting. I have to pay for it as I go. I don't have any kind of a construction loan. And I'm on disability so it's limited funds every month.. my idea was to put up a steel building, like a pole barn, and then frame up a house on the inside. Because I can do that out of the weather. And I can also leave a big enough walkway all the way around for maintenance on the inside of the pole barn. Not your typical construction project LOL. But doing it that way it gets me out of the weather, and I can put it together one room or wall at a time.
Not an expert but it looks to me like the design would be different considering your house is never exposed to the weather or sun? Moisture transfer would be much less of a problem, if any at all. I am researching because I want to build a bedroom and small living area inside a large steel building. I want it well insulated so that it cools easily with a mini-split AC unit in the Texas heat, cold weather is nonexistent therefore not even a thought. Seems with no sun and weather exposure the walls and ceiling could receive the same insulation R value. Just trying to figure out what R value is the most cost effective and efficient?
I am kinda excited to read your comment. I wish I had seen this 8 months ago when you commented because you may have already committed to a different system than I have been developing. I am a post-frame builder (pole barn). Over the years, I have had various customers turning corners of their shop into what is now called barndominiums. If you search that word, I am sure you will find various contractors' concepts. I wish I could send you a diagram of the prescriptive envelope for residential use inside a metal-clad building that I have been designing. It is very similar in concept to this double stud wall design, except the outer wall is post frame with horizontal girts instead of studs. Post-frame, as you know, is a very cost-effective framing method as opposed to the stud-wall this video uses because there is much less concrete necessary. This savings alone would improve upon the cost figures this TH-cam video presents. What many people don't realize is that the post frame still allows for virtually any architecturally pleasing finish that a stud wall does. What displeases me most when I see post frame homes is when it still looks like a pole barn with 100% metal siding when it doesn't need to. Your pole barn concept is a perfect match to your need to develop it incrementally. Build as big of a superstructure as you can afford with an adequate corner finished for living quarters - then add as you can. I knew a couple who would buy a vacant plot, build a post frame shop with a bathroom and a RV hookup inside. Then, they would live in the RV while building their dream home. Then, they would sell it at a profit and start again. What amazed me was that they had small children and still found time to do that.
The issue with ICF is that the insulation is on the wrong side. Not that it is a bad solution. But having external insulation and the advantages of thermal mass inside the conditioned space is an advantage.
@@cortlanolson1025you don't want insulation between the conditioned space and thermal mass. ICF has insulation in-between. Ideally you'd have all the insulation external to the concrete.
@@mtnbiker4480 I see what you mean. I can’t remember which company, but one of the ICF manufacturers sells a product to make the exterior insulation thicker, effectively moving the thermal mass toward the conditioned space.
I built my home in 1985 with 2 2x 4 walls 5” apart, w/ staggered studs & 2 overlapping layers of 6” fiberglass. Clad with 1x6 t&t pine over Tyvek , 6mil poly continuous envelope & 2x2 strapped for wire chase. The only issue I have had is the open nature of the stud arrangement is when a mouse gets in it can freely travel through the entire exterior wall cavity. Today I would build with a 2x4 wall with 3” polyiso in between and 2” over the interior strapped for wire and SR nailing
Neat stuff! We added 20 inches of insulation outside our log cabin, and to avoid the 'tunnel effect' out of the existing windows, we flared out the window openings horizontally at 45 degrees. The very thick walls then don't block your view!
I have been into net zero and passive house technology for years and this is the most concise and understandable video describing the reasons and techniques that I have seen. Great video guys.
I renovated a house in the late 1980's my Dad told me to go with the double system. He had helped build one in the 1960's here in Manitoba. Thanks for sharing your knowledge. I am sharing your videos with some friends who have had condensation problems.
We have worked with both double wall and exterior Ci. And I would agree with your assessment in terms of cost. Another benefit of a DSW is that at least from the exterior is that flashing and finishing while extremely important to do correctly is quite simple and familiar to most trades.
Even on an R-20 wall most of the energy loss occurs at the windows and doors. Upgrade them and make them smaller for real energy savings. Energy analysis will identify when it makes sense to upgrade the R-value of the walls.
Yes, this touches on something a lot of people don't understand with thermal efficiency. Very small inefficiencies in design can have huge effects. A single double glazed window in a wall can easily reduce the wall's effective R-value by 25-50% depending on wall and window size. The thermal bridging of fasteners for exterior insulation have an outsized effect as well, as well as metal flashings that go from the exterior to the sheathing, bypassing exterior insulation.
@@gcc8584 strength matters too...too many structures are made with a million tooth picks which works until a couple tooth picks fail and the whole structure is lost...
Do you have a video on the electrical details with the service cavity? Why not have vertical furring strips attached to the studs? With Smart vapour barrier in between.
Great video love the density of information here, as well as great explanations on issues with the double wall system, and why they exist. Regarding the 27% increase in material cost however, the amount of cost for labor will be significantly higher then the exterior insulation option, As that requires no special planning, education or oversight of the workers. I will say that, at least theoretically, the performance of this double wall can vastly exceeded that assembly, But I think it’s gonna be roughly a tie cost wise.
Does double wall system retires entirely on competent workers the more importantly experienced supervisors. You're only as good as your weakest link. If you can find a foreman who has done this many times over he will be worth his weight in gold.
13:17 235mm timber frame. mineral wool plasterboards inside or wood fibre plasterboards (services can be traced on the plaster board) Lime plaster on plasterboard (acts as vapour membrane) Wood fibre in between the timbers. Wood fibre exterior boards for continuous insulation Lime or silicone render (plaster for the outside) as weather and vapour membrane. Alternatively you could use a self adhered weather membrane on top of the wood fibre boards and install the counter battens for the rain screen cladding. Cedar cladding or cement boards would be ideal.
I built custom homes until the mid 1990’s, I am now researching building a 1200 sf dwelling with about 30% of that as a garage. I’m amazed at the changes in the building technology. My design started with high ceilings with lofts and is now no vaulted ceilings. Thanks for the video. I can envision a world in the near future where all dwellings are modular and/or pre-fabled.
I was building one of double wall house. Same idea but just regular vapor barrier (polyethylene)inside and regular membrane outside. Wood siding. Blown in cellulose insulation. So many moments about moisture removal weren't addressed a way video suggest. But it has continued insulation through gap between wall and ventilation in attic, so in theory moisture can get out this way, not horizontally, but vertically.
Thank you for your thorough explanation. My concern is finding tradespeople to do the work exceptionally well at an affordable rate. It would be interesting to know how many years the return on investment would be. It seems the more innovative ideas in reducing electricity costs the more the power companies raise their prices. One must factor in the added increase in power in the ROI.
i did precast wall with styrofoam as the bottom mold. It got me 4" of styrofoam all around my house and another 4 inches of concrete. I feel the materials are a bit more expensive than wood, but my walls went up in one day and are made in a factory so far less labor mistakes.
Very nice! One thought I'd like to run by you is regarding the windows. Living near a major airport, I've seen some applications where two dual pain windows are installed, one behind the other. The deep walls in your application look like a perfect fit for this, but I was wondering what your thought is on it? Thank you kindly
If i was building a double wall assembly, which i always thought of. There would be NO insulation between the interior wall stud, and the vapour barrier would be behind the interior wall. That reduce the potential of hole and leak in the vapour barrier caused by simple things like hangers, frame hooks, electrician, plumber etc... it would leave 2.5 or 3.5inches to run utilities, to install blocking, to hang stuff without perforating the vapour barrier
We installed all our services (plumbing, electrical etc.), then installed the drywall before dense-packing cellulose in our walls. The walls are solid insulation. In a cold climate, anything less would be crazy.
I actually have an article breaking down my thoughts on the T-Stud that I wrote a while back, you can find it here: asiri-designs.com/resources-1/f/is-tstud-wall-framing-worth-it?blogcategory=Walls
If you do furring strips on the inside before Sheetrock, wouldn’t you have to put all electrical in conduit as it would not be set back enough? Using conduit rather than romex would be a big labor and supply increase.
I renovated an old service station into a double wall on a floating floor. 360 ° radiant foil against the outer wall studs, 3 layers of r 12 fiber between the outer and inner wall studs, then another layer of radient foil. I've never had cold walls.
You answered all of my questions about windows and building science (i.e. how is the water management addressed at the bottom of windows to prevent moisture from entering the house.) and I like the price breakdown of the different wall assembly options.
Can I install the intello plus smart vapor on the inside of the exterior 2×4 thereby having my sealed interior smart vapor barrier and removing the interior furring channel for ease of install of electrical etc.
So, the Intello Plus acts to minimize vapor penetration to the interior of the wall, yet allows any vapors which may accumulate, to migrate from within the wall to the interior space. In the meantime the Blueskin VP100 prevents vapor penetration from the outside environment to the interior of the perimeter walls. Is this a correct understanding?
What are your thoughts on using a Zip (R6) sheathing instead of the wrap and plywood if building a home in Climate Zone 3 (northern Oklahoma)? We run AC about 90% of the year and turn the heat on maybe 5% of the year. Big fan of your videos… thank you.
Zip-R provides a nice thermal break. But you can get the same or better results with OSB/CDX sheathing + WRB + rigid insulation. Go with whichever is most cost effective. Prices fluctuate a lot these days.
Great, informative video mate. Been designing my off grid home for over a year and the insulation part has been a nightmare. Prices for exterior insulation are near highway robbery.
Wow! What an awesome video! Thanks so much for sharing your expertise! It’s given me a lot to think about for when I start the build on my lot here in Texas! 🤠
Great job. I've been looking at 2x6 24 OC walls with Zip and rigid wood fiber insulation on the exterior but now I'm looking at double stud walls again. So many choices and so hard to decide.
Thanks so much for the excellent details on this and the cost comparison. I'm interested in discussing a project and filled out the form on your web-site.
Nice video and I checked out your website. Another benefit to double wall construction is sound mitigation. Wall designs for video and audio studios, and other buildings use double wall construction to reduce sound transference much like reducing heat transference thru the studs. Cheers
I am torn whether to go after a double wall (I am in Minnesota) or exterior continuous. I would strive to get all the interior/exterior air sealing right either way, but having a cold surface on the inside of the sheeting has innate risks. At the same time, hitting studs every time with the hundreds of blind screws of an exterior continuous insulation and rainscreen is tricky too. It seems like the building industry moves very slowly and there has to be a simple to execute exterior insulation that will eventually become an established and commonplace solution - long blind screws will never be easy.
For the people living in the US this will of course make your house hurricane-proof as well, which is a nice side-benefit. As a person living in Sweden the shoddy building standards in the US honestly amazes me, triple-glazed windows here are standard, our house is 16 years old now and has triple-glazed windows all-around, proper insulation and a ground-source heat pump, something only a fraction of all the new homes in the US seemingly have. Seems very short-sighted since it saves you so much money in the long run.
Sweden is not even close to the USofA with regard to climate conditions. In the US, the demand is on cooling the indoor environment. In the sunbelt we can have up to 8 to 9 months of cooling required where in Sweden one may never see the need for additional cooling for interior spaces.
@@Wegl79 Well insulation works both ways. It has the same effect in reducing the amount of AC you need to use as it does in reducing the amount of heating you need to use. If you'd place a Swedish house in Arizona it'd still use less than half as much electricity as a US house, because it'd barely heat up in the first place and as such wouldn't need much AC.
We use square notched timber frames. Window and door bays get spray foam and the bays next to them. The doors and windows get thermal breaks not thermal gaps around them. Usually zip sheating and mineral wool. The timber frame actually saves money on labor and lumber. The mineral wool in my masonry north wall and under slab was expensive. Building a passive solar earthship like Goldie and Matt's but no berm or tires. Plus their framing wasn't well thought out and I needed more roof pitch. I need 70 psf snow loads and 6 foot frost depths also. We use glulam 2x10's or 12's for beams. At 50-75$ for 16 foot beam and can make longer. Lvl need too much lateral bracing. A.I. really helps with cost and design considerations. Sure you have seen how flimsy lvl can be. Which glulam beams allow for 2x4 or less on the flats for double stud walls since not structural. Price goes up on wood every time it gets milled down and more wood stamps cost money too. But if you don't have local lumber mills the price for timber frame jumps. As the cost of shipping increases. It's why we use local masonry material and timbers. Right now shipping on rock and stone cost as much as the rock and stone. 800$ for 40 tons cost 800$ to be dropped on site. We do a lot of masonry work. Why give the cement company the money we could get for labor. We build a lot of A frames and skillion designs. I see where the double studs would be better like earth quake zones. If I build a walk in cooler I will use double studs for sure. Because hvac equipment hanging and on top of them. Set of framing for equipment and one for structure. Minimize the vibrations.
Blown in cellulose, wool, and other loose fill insulations settle over time meaning the top several feet of a wall may not have any insulation after a few years as it all settle downward compressing the insulation in the lower part of the wall lowering its R-value. Two ways to make a super efficient house ICF construction uses lots of highly insulative foam and the thermal mass of the 6 plus inch thick concrete core plus the fact that ICF homes are super air tight or just use 2x12's and have spray foam installed in two 5.75" thick applications a week or so apart so off gassing can occur after the first application.
The cost of this breaks down alright if you've got the money. I'm really curious as to the cost of repair however. Someone with a handheld drywall saw can poke thru that vapor barrier inside. and if you live somewhere with hurricanes. the outer wall could easily be hit and damaged with debris. again damaging the vapor barriers. Not much you can do when your house gets wacked with debris and you've got 7 more hours of whirling rain and wind to go. basically blowing it into the damaged area. Cost of repair is very important to me.
If you are running services in the interior cavity with the furring strips then how are you putting nail flanges in front of wires and pipes when the only layer above them is the drywall?
On the interior wall, do you need to tape behind where you plant to install the furring strips (where they will be attached to the studs) or does the 2x3 furring strip itself provide enough the air barrier/prevent air leakage?
Windows are never efficient compared to even the most basic wall. Installing any window is a sacrifice to efficiency in exchange for beauty. So design your building accordingly. Smart, minimal, and small, and non-operable window placement will always beat trying to increase the efficiency of a window itself. It's possible for double-pane to be the smarter (more economic ROI) choice over triple-pane if you optimized accordingly, and I'm not talking about the whole "passive" house element: which is a good option when you really value beauty, but are still moderately concerned about efficiency. A modern non-window home will always perform better than a window home, regardless of how well you place the windows, or how much money you throw at the windows.
As high as possible and your budget allows. Also, fewest windows on the east and west sides as possible, and spring for higher R value windows on the north elevation than the south.
how do you account for electrical penetrations in the interior GWB assembly? the battens + 1/2" GWB = 2"Depth yes? i would guess customers would need to be given options between having cake / eating cake when it comes to the selection of electrical fixture types and placement ( to maintain a sealed interior air barrier in a real world building situation) ?
@@histershellac2842 The GWB isn't the air barrier in this assembly, it's the smart vapor retarder membrane (this is also why we have that service cavity provided by the 2x3 strapping). Anything that has to penetrate the smart vapor retarder is either taped or gasketed.
Just use external insulation and in between the timber, easily achieving passive house standards and no thermal bridging while keeping it simple and easy to build. For humidity and drying out just use highly vapour permeable materials such as: Wood fibre, hemp, sheep wool, aerogel wool, grass, cork, lime plaster or clay plaster. For vapour control you can build with a vapour class 1 barrier on the inside close to the plaster board to stop humidity and use a vapour permeable weather membrane on the outside with a cab of at least 80mm between the membrane and rain screens ventilated façade. Or you can just use a completely vapour open structure by using plaster on the inside (lime or clay based) and render or ventilated cladding on the outside. there’s the option of a intelligent vapour membranes as well (it allows vapour in or out based on the quantity)
@ASIRIDesigns - could you use a Zip assembly with 1" of closed cell spray foam on the interior side of the sheathing to avoid mold/rot issues (or potentially Zip R without the need for spray foam)? This 1" of closed cell would act as a vapor/air barrier and not allow moisture to condense on the backside of the sheathing, and would be installed prior to the cellulose dense pack...or would this create other unforeseen issues if you were in say a zone 4 climate?
My house is 50 years old. I plan to change the outer wood panels next summer. I also like to improve the insulation with rockwool and better vapour retarders. Do you think I can put in new vapour retarders without removing the internal drywall(gypsum board)? Can I just put the vapour retarder at the cavities and tape it well on the studs? Thanks.
What about doing all this but with a continuous top and bottom plate of either 2x8, 2x10, or 2x12 for both strength and simplicity? Also if you shouldn't overlap stud positions even if they don't touch in order to minimize thermal bridging, how do you handle the structural integrity of the corners of the house while also having a place for the sheathing, both interior and exterior, to attach at those points? Also, can you add Zip-R to either method or is that not cost-effective? Lastly, can you do this with 2x3 studs on a 2x6 plate for the interior walls in order to maximize sound deadening on a budget without making hugely thick walls, or are there better options, especially for the 20-80hz range, which, to my knowledge, no conventional sound damping method can really control? PS, have you heard about aerosolized caulk treatment for air sealing? They pressurize your house with a fan like the blower door test, then set off canisters of aerosolized caulk which will find gaps up to 3/8 thick/dia and seal them up. Ideally, this would be done after all the framing, sheathing, windows, doors, and MEP rough-ins/penetrations are complete, but before the insulation, interior sheathing, and final exterior cladding or outsulation are done.
Great video. I have a brick veneer 100mm cavity, 75mm stud walls with Gyprock interior sheet walls. How's best way to insulate these walls? Will blow in cellulose works?
Great video on explaining double wall construction. I plan on doing this on a future cabin build. I'd like to add rockwool to the exterior with a cement board exterior for improving fire resistance. What product do you recommend using to attach/support the exterior cement exterior finishing ? I don't want to use a lumber product due to potential heat transfer & damage from a forest fire. Thx. PS: What is your profession ?
Amazing information and presentation. You helped me to understand a couple B.S. concepts i've been curious about for a while. I've been building with an emphasis on exterior permeability for a few years now. But what happens if you go to all the trouble to make the interior permeable, and then paint over it with a plastic (Acrylic latex) paint? It cuts off all permeability through the drywall, no? I personally like mineral-based paints, but that's certainly not the standard. Thanks again!
Fantastic video and I love the building science, however cost to benefit is a concern. If I build a house that I heat w a candle (net zero) vs a non insulated house that breathes well w no drawbacks other than heating cost. My cheap 100k stick home costs me $200 per month to heat over 30y is roughly 8k and the savings wouldn’t cover the insulation let alone health concerns. We can still do better.
I live in central Texas. Winters are mild and summers usually have 30+ days of 100 degrees or more. What would be the difference on how the wall is as it goes with interior wall design.......
Great video. I appreciate the detailed wall assembly diagrams. The pace, visuals, explanations, all good. Question: Do you use standard sized outlet boxes or a smaller box to fit into the service cavity depth?
Wonderful video and amazing diagrams. Very clear and simple to understand. How does using something like Zip R-9 and 2x6 wall compare to a double wall assembly? Do you have a sense of where it would be as cost comparison?
Very informative video. I could be mistaken, but I thought it was recommended to use real plywood when is comes to sheathing since it has faster drying time in the event it gets wet. If so, wouldn't that rule out using ZIP system sheathing since it is OSB covered with a fluid air barrier?
I wonder what the cost breakdown comes out to be if you're doing a retrofit? I'd imagine throwing on exterior insulation and re cladding is going to be the winner in that case.
I'm so glad I stumbled upon this video. Consise, up to the point and covering all details. Subsribed. One note- the l double stud wall will be more labor intensive, would be nice to get a rough idea of increase in man hours.
How would I hang stuff like kitchen cabinet on the drywall + 2*3 horizontal furring? I feel the 2 inch thick furring is not thick enough to hang kitchen cabinet. Also would it be a problem if some of the screw mistakenly break the smart vapor retarder?
The comparison of the zip and 2x6 to the blue and 2x4 double leaves me wondering about a mix of the two. Double wall with zip and Roxul insulated. I’ m all in for the non poly vapour barrier, but wondering what the benefits are to the ply and blue over zip if both are vapour retardant?
Great video!!! Very informative. I wonder if you can do a similar video taking into account the cost of labor (even if it's just the cost of labor in your immediate area, just for comparison) and compare the single wall with exterior insulation, to this double wall system, to a SIP wall system, ICFs systems and perhaps even a HempCrete with Just BioFiber System. Even if you didn't go into all the details as thorough as what this video has, it would be tremendously informative for anyone looking to build a new house to see what the ACTUAL cost of a wall system per square foot is. Again, even if you compare it only in your area, at least, people can gauge apples to apples in one area. They can just do calculations for their areas afterwards.
Awesome video, I was curious the difference between using a separate ply and air barrier for sheathing on the exterior wall instead of using zip sheathing?
Thank you - Simply put, plywood has a significantly better drying potential compared to OSB, as plywood can become up to seven times more permeable when it gets "wet", whereas OSB does not. The self-adhered membrane is also more vapor open than the coating on the ZIP sheathing. When it comes to these super insulated walls, it's crucial that they have the ability to dry out if/when they get wet.
I got more out of this one video than I did from dozens and dozens of other videos. The price breaks are fantastic! You just saved me days of work. Please do more.
So glad to hear it was helpful! Cheers!
@@ASIRIDesigns absolutely. Thanks a lot
Nah
I have 3 crews doing 3 places right now and was thinking of doing this. I’m not doing it. Not for these. I’ll wait for a halo project and up my game in efficiency. But, damn if that wasn’t the most informative video I’ve seen on double studding.
I’ve watched a bunch of videos that were much longer and did not give the details that I needed to feel confident enough to try it without the moisture issues that pop up in every other video on this subject.
It’s like these builders wanna ACT like they’re showing you how to do a new and awesome technique, while at the same time, withholding those details that complete the picture.
Then, they do a commercial.
Great video. Very informative and eye opening.
THANKS!
@@ASIRIDesigns Very good presentation. I built with double stud walls spaced 4.5" apart for R-44 insulation. Did not spring for the triple pane windows so that is my weak point but with 9.9kW solar array my house generates more energy than it uses each year- with enough extra to power two EVs. The double stud walls do help a lot with noise and since I built them myself the extra cost was not all that bad in 2014. Lumber has gone up a lot since then. Really any competent framing crew should be able to build double-stud and watching this video will educate them on how to install the windows. Thanks for providing the numbers also. One thing people should think about is the long term cost of poor insulation- it is so nice to never have any electric bill.
I was able to understand everything in this video thanks to your vocabulary and delivery of information. This video is incredible! Great job
Same - extremely efficient & detailed & concise.
I could be wrong, since there are so many different materials involved, but I think the double wall system also allows for more acoustic insulation. That may be a consideration for some people, particularly in an urban or busy suburban area.
Yea cause it's decoupled. It's sometimes done for bathrooms so you can't hear the shower among other things
@@redneckcoder gotta pay the bills somehow 🤣
The stud is the main transmission of sound vibration from side to the other. When the two sides of the wall aren't connected to the same stud, sound is dramatically reduced. Interior walls can use staggered studs, where they are alternately moved a half inch off center from the previous stud. You would need stronger wall material to span twice the distance or put the studs more frequent, like 12 or 8 inches apart.
@@redneckcoder Both contribute, and the dampening effect of insulation helps a lot, but wood is a far greater conductor of sound than air. That's not my opinion. There's charts you can refer to with real measurements of many materials. Having wallboard connected to the stud makes it move together as one, whereas sound hitting between the studs has to transfer from air to board to air to board and then to air again, each time losing energy.
@@redneckcoder Ah, you're right; I did miss your point. I apologize.
This is some of the best and most concise advice I’ve found online. Very helpful work here sir.
I haven't watched any other of your videos but this single handedly caused me to subscribe and and see what else you got. Absolutely amazing video.
Great stuff as always. Double walls also provide a huge reduction in sound transmission for those in noisy neighborhoods. If maximum thermal efficiency is the goal, then double walls are practically impossible to beat. However... the labor costs are a HUGE factor here. The cost to install exterior EPS/XPS will be drastically cheaper than having a crew frame out double walls and the extra details for fenestrations. And for most areas of the country, the difference between R40 (R21 cavity + 4" of rigid foam) and R60 might not even be noticeable. You'd probably be better off putting that extra money into upgraded windows and doors. Building double walls with double-pane windows would be pretty pointless, for example.
No extra window details for 4" of exterior foam? I agree that going from 40 to 60 won't be very noticeable, diminishing returns.
@@rodfreess6019 Some extra details for sure but it's flashing and trim/bucks which you would need to do in either case.
@@DeuceDeuceBravo I would consider double walls just for the superior sound proofing alone. However, the configurations is different because you ideally want an air gap between each wall.
You know what I would love to see you do? A similar video on the all-out best wall assembly you can imagine, disregarding budget. Joe Lstiburek has a brief mention of the "institutional wall" but really doesn't go into details. I'm curious what something like that would look like. Basically infinite budget, but using actual building materials (no stuffing theoretical aerogel in the wall or something like that).
Perfect wall IMO.. will be a "p
Perfect Block" wall. No infinite budget needed.
@@mindtrap0289 Interesting, could you explain more? I'm not a builder or structural engineer or anything, but just curious. I tried googling "p perfect block" and "perfect block wall" and nothing specific really came up.
Yep, block wall, exterior continuous thermal insulation. No thermal breaks.
Outstanding! Thank you for the clarity of presentation, the walkthrough on the details and the cost breakdown.
I would love a video on leaving rafters exposed and insulating outside of the roof. We haven't figured out best way or a way we like yet. Being able to leave rafters exposed with roof board saves finishing money.
In Germany there is a type of wood based insulation popular that you can install onto the rafters. (Steico Dry) It is so stable that you can walk on the temporary wall and is weather proof for a couple of weeks until the finished roof is installed.
As a bonus: If you use these wood based insulations you can build you roof without a vapour barrier because it is permeable and capillary active so that condesing water is transported to the warmer (and dryer) side of the insulation.
Steico offers details for timber framed buildings on their website, the roof is basically from the inside to the outside: Rafters, Insulation (Steico Dry), sarking membrane (for weather proofing), roof battens, some sort of roof tiles.
It is a more expensive type of insulation but you can renovate your roof completely from the outside and keep your rooms as they are without having to worry about the correct vapour barrier.
If I was building again, I would consider the double frame walls. But you would have to know that the work crews really understood the project and what detail has to be taken to achieve the correct level of efficiency. This would be a nightmare if corners were cut and later down the road, you came up with all your walls were filled with mold! Love the idea, but a lot of workers seem to be lacking in their effort to a proper job!
Well done!
I built in1986 , staggered 2x4 stud walls 5” apart with 2 r19 fiberglass batts. 1 disadvantage is if or when mice get into the wall cavity they can travel freely. Otherwise I would do it again!
Needed a fire block stud every 10 ft...
If the cavity is filled with insulation isn't that a fire block?
@@AngelMalakimI think he means a mouse barrier
I’m planning a house now and mice are a huge problem here. I’m trying to decide between doing exactly what you did, or just sticking with 2x6 walls. This video also advocates for a gap behind siding, which is another runway for mice. Any other issues with your staggered wall.?
@ do you use ply web I beams for studs in your neck of the woods? It is a solution in UK / EU.
I'm totally sold on the double wall design. At the cost is daunting. I have to pay for it as I go. I don't have any kind of a construction loan. And I'm on disability so it's limited funds every month.. my idea was to put up a steel building, like a pole barn, and then frame up a house on the inside. Because I can do that out of the weather. And I can also leave a big enough walkway all the way around for maintenance on the inside of the pole barn.
Not your typical construction project LOL.
But doing it that way it gets me out of the weather, and I can put it together one room or wall at a time.
Not an expert but it looks to me like the design would be different considering your house is never exposed to the weather or sun? Moisture transfer would be much less of a problem, if any at all. I am researching because I want to build a bedroom and small living area inside a large steel building. I want it well insulated so that it cools easily with a mini-split AC unit in the Texas heat, cold weather is nonexistent therefore not even a thought. Seems with no sun and weather exposure the walls and ceiling could receive the same insulation R value. Just trying to figure out what R value is the most cost effective and efficient?
I am kinda excited to read your comment. I wish I had seen this 8 months ago when you commented because you may have already committed to a different system than I have been developing.
I am a post-frame builder (pole barn). Over the years, I have had various customers turning corners of their shop into what is now called barndominiums. If you search that word, I am sure you will find various contractors' concepts.
I wish I could send you a diagram of the prescriptive envelope for residential use inside a metal-clad building that I have been designing. It is very similar in concept to this double stud wall design, except the outer wall is post frame with horizontal girts instead of studs.
Post-frame, as you know, is a very cost-effective framing method as opposed to the stud-wall this video uses because there is much less concrete necessary. This savings alone would improve upon the cost figures this TH-cam video presents. What many people don't realize is that the post frame still allows for virtually any architecturally pleasing finish that a stud wall does. What displeases me most when I see post frame homes is when it still looks like a pole barn with 100% metal siding when it doesn't need to.
Your pole barn concept is a perfect match to your need to develop it incrementally. Build as big of a superstructure as you can afford with an adequate corner finished for living quarters - then add as you can. I knew a couple who would buy a vacant plot, build a post frame shop with a bathroom and a RV hookup inside. Then, they would live in the RV while building their dream home. Then, they would sell it at a profit and start again. What amazed me was that they had small children and still found time to do that.
There is a home in Sweden that has a completely glass enclosure around it.
I’d be curious to know how the cost of this compares to ICF?
I’m betting with the labor cost included in all this makes more expensive than icf
The issue with ICF is that the insulation is on the wrong side. Not that it is a bad solution. But having external insulation and the advantages of thermal mass inside the conditioned space is an advantage.
@@imkindofabigdeal4308 I’ve never heard of the insulation being on the wrong side with ICF. What do you mean by that?
@@cortlanolson1025you don't want insulation between the conditioned space and thermal mass. ICF has insulation in-between. Ideally you'd have all the insulation external to the concrete.
@@mtnbiker4480 I see what you mean. I can’t remember which company, but one of the ICF manufacturers sells a product to make the exterior insulation thicker, effectively moving the thermal mass toward the conditioned space.
I built my home in 1985 with 2 2x 4 walls 5” apart, w/ staggered studs & 2 overlapping layers of 6” fiberglass. Clad with 1x6 t&t pine over Tyvek , 6mil poly continuous envelope & 2x2 strapped for wire chase.
The only issue I have had is the open nature of the stud arrangement is when a mouse gets in it can freely travel through the entire exterior wall cavity.
Today I would build with a 2x4 wall with 3” polyiso in between and 2” over the interior strapped for wire and SR nailing
Neat stuff! We added 20 inches of insulation outside our log cabin, and to avoid the 'tunnel effect' out of the existing windows, we flared out the window openings horizontally at 45 degrees. The very thick walls then don't block your view!
Love the content! Best explained engineer TH-cam channel
I wish you would’ve added to this video how to do the roof/ceiling installation detail design
I have been into net zero and passive house technology for years and this is the most concise and understandable video describing the reasons and techniques that I have seen. Great video guys.
I renovated a house in the late 1980's my Dad told me to go with the double system. He had helped build one in the 1960's here in Manitoba. Thanks for sharing your knowledge. I am sharing your videos with some friends who have had condensation problems.
We have worked with both double wall and exterior Ci. And I would agree with your assessment in terms of cost. Another benefit of a DSW is that at least from the exterior is that flashing and finishing while extremely important to do correctly is quite simple and familiar to most trades.
Even on an R-20 wall most of the energy loss occurs at the windows and doors. Upgrade them and make them smaller for real energy savings. Energy analysis will identify when it makes sense to upgrade the R-value of the walls.
This.
Yes, this touches on something a lot of people don't understand with thermal efficiency. Very small inefficiencies in design can have huge effects. A single double glazed window in a wall can easily reduce the wall's effective R-value by 25-50% depending on wall and window size. The thermal bridging of fasteners for exterior insulation have an outsized effect as well, as well as metal flashings that go from the exterior to the sheathing, bypassing exterior insulation.
Triple pane windows with 2x4 studs is more efficient then 2 pane windows with 2x12 studs.
@@gcc8584 strength matters too...too many structures are made with a million tooth picks which works until a couple tooth picks fail and the whole structure is lost...
They have R-20 windows now. In a few years the vacuum insulated glazing units will hit the market and we will see even higher r ratings.
Do you have a video on the electrical details with the service cavity? Why not have vertical furring strips attached to the studs? With Smart vapour barrier in between.
Great video love the density of information here, as well as great explanations on issues with the double wall system, and why they exist.
Regarding the 27% increase in material cost however, the amount of cost for labor will be significantly higher then the exterior insulation option,
As that requires no special planning, education or oversight of the workers.
I will say that, at least theoretically, the performance of this double wall can vastly exceeded that assembly,
But I think it’s gonna be roughly a tie cost wise.
Dense packed information. I would love to see those kind of cost reflected in a future video too!
Does double wall system retires entirely on competent workers the more importantly experienced supervisors.
You're only as good as your weakest link.
If you can find a foreman who has done this many times over he will be worth his weight in gold.
Since we can't use vinyl on the interior how many coats of paint are okay before we should be worried about preventing drying through the drywall?
13:17 235mm timber frame.
mineral wool plasterboards inside or wood fibre plasterboards (services can be traced on the plaster board)
Lime plaster on plasterboard (acts as vapour membrane)
Wood fibre in between the timbers.
Wood fibre exterior boards for continuous insulation
Lime or silicone render (plaster for the outside) as weather and vapour membrane.
Alternatively you could use a self adhered weather membrane on top of the wood fibre boards and install the counter battens for the rain screen cladding.
Cedar cladding or cement boards would be ideal.
I was warm and cozy just watching this video.
I built custom homes until the mid 1990’s, I am now researching building a 1200 sf dwelling with about 30% of that as a garage. I’m amazed at the changes in the building technology. My design started with high ceilings with lofts and is now no vaulted ceilings.
Thanks for the video. I can envision a world in the near future where all dwellings are modular and/or pre-fabled.
That's not a world I want to live in.
I was building one of double wall house. Same idea but just regular vapor barrier (polyethylene)inside and regular membrane outside. Wood siding. Blown in cellulose insulation. So many moments about moisture removal weren't addressed a way video suggest. But it has continued insulation through gap between wall and ventilation in attic, so in theory moisture can get out this way, not horizontally, but vertically.
Thank you for your thorough explanation. My concern is finding tradespeople to do the work exceptionally well at an affordable rate.
It would be interesting to know how many years the return on investment would be. It seems the more innovative ideas in reducing electricity costs the more the power companies raise their prices. One must factor in the added increase in power in the ROI.
i did precast wall with styrofoam as the bottom mold. It got me 4" of styrofoam all around my house and another 4 inches of concrete. I feel the materials are a bit more expensive than wood, but my walls went up in one day and are made in a factory so far less labor mistakes.
Very nice!
One thought I'd like to run by you is regarding the windows.
Living near a major airport, I've seen some applications where two dual pain windows are installed, one behind the other.
The deep walls in your application look like a perfect fit for this, but I was wondering what your thought is on it?
Thank you kindly
How about triple pane windows in Canada
I think this is the best video I've ever seen on anything.
I just learned how to build my cabin.
Great video, I'm looking to build a home in Calgary in a few years so this was insightful. I will be watching more
If i was building a double wall assembly, which i always thought of. There would be NO insulation between the interior wall stud, and the vapour barrier would be behind the interior wall. That reduce the potential of hole and leak in the vapour barrier caused by simple things like hangers, frame hooks, electrician, plumber etc... it would leave 2.5 or 3.5inches to run utilities, to install blocking, to hang stuff without perforating the vapour barrier
He shows furring strips on the interior that does this. 7:27 but it's a good point to make.
What you can get away with depends on the climate.
The problem is that Americans are addicted to wooden walls in the west. Such a disaster
We installed all our services (plumbing, electrical etc.), then installed the drywall before dense-packing cellulose in our walls. The walls are solid insulation. In a cold climate, anything less would be crazy.
It'll be interesting to see your comparison of the T-stud or thermal stud wall assembly.
I actually have an article breaking down my thoughts on the T-Stud that I wrote a while back, you can find it here: asiri-designs.com/resources-1/f/is-tstud-wall-framing-worth-it?blogcategory=Walls
@@ASIRIDesigns vip versus milled log ?
If you do furring strips on the inside before Sheetrock, wouldn’t you have to put all electrical in conduit as it would not be set back enough? Using conduit rather than romex would be a big labor and supply increase.
I renovated an old service station into a double wall on a floating floor. 360 ° radiant foil against the outer wall studs, 3 layers of r 12 fiber between the outer and inner wall studs, then another layer of radient foil. I've never had cold walls.
You answered all of my questions about windows and building science (i.e. how is the water management addressed at the bottom of windows to prevent moisture from entering the house.) and I like the price breakdown of the different wall assembly options.
Can I install the intello plus smart vapor on the inside of the exterior 2×4 thereby having my sealed interior smart vapor barrier and removing the interior furring channel for ease of install of electrical etc.
So, the Intello Plus acts to minimize vapor penetration to the interior of the wall, yet allows any vapors which may accumulate, to migrate from within the wall to the interior space. In the meantime the Blueskin VP100 prevents vapor penetration from the outside environment to the interior of the perimeter walls. Is this a correct understanding?
What are your thoughts on using a Zip (R6) sheathing instead of the wrap and plywood if building a home in Climate Zone 3 (northern Oklahoma)?
We run AC about 90% of the year and turn the heat on maybe 5% of the year.
Big fan of your videos… thank you.
Zip-R provides a nice thermal break. But you can get the same or better results with OSB/CDX sheathing + WRB + rigid insulation. Go with whichever is most cost effective. Prices fluctuate a lot these days.
Great, informative video mate. Been designing my off grid home for over a year and the insulation part has been a nightmare. Prices for exterior insulation are near highway robbery.
Interesting presentation, thank you. Also my compliments on your details and thorough walk-through.
Wow! What an awesome video! Thanks so much for sharing your expertise! It’s given me a lot to think about for when I start the build on my lot here in Texas! 🤠
I liked the double top plate detail that leaves the insulation cavity all the way floor to ceiling. Nice.
What if you did precast concrete walls .There's a company where I am in NC that gets R 22 from their walls .I'm thinking basement and first floor.
At 3:19 Is it a good idea to have a seam in the subfloor for the air barrier?
this is a great video with clear explanations and great illustrations/ cost basis. would love to see more
Great video! Thank you. I’m also curious about the comparison to insulated CMU systems like comfort block or Omni block.
Great job. I've been looking at 2x6 24 OC walls with Zip and rigid wood fiber insulation on the exterior but now I'm looking at double stud walls again. So many choices and so hard to decide.
Thanks so much for the excellent details on this and the cost comparison. I'm interested in discussing a project and filled out the form on your web-site.
Fantastic overview. This helped me decide that double wall insulation is untenable for my use case.
Would love to see how this compares to ICF in cost and your opinion on the pros and cons of rach system.
Nice video and I checked out your website. Another benefit to double wall construction is sound mitigation. Wall designs for video and audio studios, and other buildings use double wall construction to reduce sound transference much like reducing heat transference thru the studs. Cheers
I am torn whether to go after a double wall (I am in Minnesota) or exterior continuous. I would strive to get all the interior/exterior air sealing right either way, but having a cold surface on the inside of the sheeting has innate risks. At the same time, hitting studs every time with the hundreds of blind screws of an exterior continuous insulation and rainscreen is tricky too. It seems like the building industry moves very slowly and there has to be a simple to execute exterior insulation that will eventually become an established and commonplace solution - long blind screws will never be easy.
Nice video! suggestion for the cost breakdowns, either sort by price descending or arrange from exterior to interior or interior to exterior location
For the people living in the US this will of course make your house hurricane-proof as well, which is a nice side-benefit.
As a person living in Sweden the shoddy building standards in the US honestly amazes me, triple-glazed windows here are standard, our house is 16 years old now and has triple-glazed windows all-around, proper insulation and a ground-source heat pump, something only a fraction of all the new homes in the US seemingly have. Seems very short-sighted since it saves you so much money in the long run.
Sweden is not even close to the USofA with regard to climate conditions. In the US, the demand is on cooling the indoor environment. In the sunbelt we can have up to 8 to 9 months of cooling required where in Sweden one may never see the need for additional cooling for interior spaces.
@@Wegl79 Well insulation works both ways. It has the same effect in reducing the amount of AC you need to use as it does in reducing the amount of heating you need to use.
If you'd place a Swedish house in Arizona it'd still use less than half as much electricity as a US house, because it'd barely heat up in the first place and as such wouldn't need much AC.
We use square notched timber frames. Window and door bays get spray foam and the bays next to them. The doors and windows get thermal breaks not thermal gaps around them. Usually zip sheating and mineral wool. The timber frame actually saves money on labor and lumber. The mineral wool in my masonry north wall and under slab was expensive. Building a passive solar earthship like Goldie and Matt's but no berm or tires. Plus their framing wasn't well thought out and I needed more roof pitch. I need 70 psf snow loads and 6 foot frost depths also. We use glulam 2x10's or 12's for beams. At 50-75$ for 16 foot beam and can make longer. Lvl need too much lateral bracing. A.I. really helps with cost and design considerations. Sure you have seen how flimsy lvl can be. Which glulam beams allow for 2x4 or less on the flats for double stud walls since not structural. Price goes up on wood every time it gets milled down and more wood stamps cost money too. But if you don't have local lumber mills the price for timber frame jumps. As the cost of shipping increases. It's why we use local masonry material and timbers. Right now shipping on rock and stone cost as much as the rock and stone. 800$ for 40 tons cost 800$ to be dropped on site. We do a lot of masonry work. Why give the cement company the money we could get for labor. We build a lot of A frames and skillion designs. I see where the double studs would be better like earth quake zones. If I build a walk in cooler I will use double studs for sure. Because hvac equipment hanging and on top of them. Set of framing for equipment and one for structure. Minimize the vibrations.
Could you add a detail outlining the loss of square footage interior space for r60 double stud vs 2x6. Thanks.
Blown in cellulose, wool, and other loose fill insulations settle over time meaning the top several feet of a wall may not have any insulation after a few years as it all settle downward compressing the insulation in the lower part of the wall lowering its R-value. Two ways to make a super efficient house ICF construction uses lots of highly insulative foam and the thermal mass of the 6 plus inch thick concrete core plus the fact that ICF homes are super air tight or just use 2x12's and have spray foam installed in two 5.75" thick applications a week or so apart so off gassing can occur after the first application.
I wish we could get this quality of design and content to help with building in hot and humid climates like 1A.
It’s so hard to find details for zone 1 :(
Fear not! I've got some videos planned for my friends down South :)
The cost of this breaks down alright if you've got the money. I'm really curious as to the cost of repair however. Someone with a handheld drywall saw can poke thru that vapor barrier inside. and if you live somewhere with hurricanes. the outer wall could easily be hit and damaged with debris. again damaging the vapor barriers. Not much you can do when your house gets wacked with debris and you've got 7 more hours of whirling rain and wind to go. basically blowing it into the damaged area. Cost of repair is very important to me.
Labor comparison would be great!
05:00 - Could you treat the OSB with some anti-fungus to make it a useable solution?
If you are running services in the interior cavity with the furring strips then how are you putting nail flanges in front of wires and pipes when the only layer above them is the drywall?
Excellent detail and design! Thank you
On the interior wall, do you need to tape behind where you plant to install the furring strips (where they will be attached to the studs) or does the 2x3 furring strip itself provide enough the air barrier/prevent air leakage?
If we design a wall with R40, how efficient do the windows need to be ?
window efficiency will be critical to increase wall R value.
I'd like to know that too
Windows are never efficient compared to even the most basic wall. Installing any window is a sacrifice to efficiency in exchange for beauty. So design your building accordingly. Smart, minimal, and small, and non-operable window placement will always beat trying to increase the efficiency of a window itself. It's possible for double-pane to be the smarter (more economic ROI) choice over triple-pane if you optimized accordingly, and I'm not talking about the whole "passive" house element: which is a good option when you really value beauty, but are still moderately concerned about efficiency. A modern non-window home will always perform better than a window home, regardless of how well you place the windows, or how much money you throw at the windows.
As high as possible and your budget allows.
Also, fewest windows on the east and west sides as possible, and spring for higher R value windows on the north elevation than the south.
how do you account for electrical penetrations in the interior GWB assembly? the battens + 1/2" GWB = 2"Depth yes? i would guess customers would need to be given options between having cake / eating cake when it comes to the selection of electrical fixture types and placement ( to maintain a sealed interior air barrier in a real world building situation) ?
@@histershellac2842 The GWB isn't the air barrier in this assembly, it's the smart vapor retarder membrane (this is also why we have that service cavity provided by the 2x3 strapping). Anything that has to penetrate the smart vapor retarder is either taped or gasketed.
Yeah, excluding the labor costs. That will be driven up significantly with all the different systems to work together.
Just use external insulation and in between the timber, easily achieving passive house standards and no thermal bridging while keeping it simple and easy to build.
For humidity and drying out just use highly vapour permeable materials such as:
Wood fibre, hemp, sheep wool, aerogel wool, grass, cork, lime plaster or clay plaster.
For vapour control you can build with a vapour class 1 barrier on the inside close to the plaster board to stop humidity and use a vapour permeable weather membrane on the outside with a cab of at least 80mm between the membrane and rain screens ventilated façade.
Or you can just use a completely vapour open structure by using plaster on the inside (lime or clay based) and render or ventilated cladding on the outside.
there’s the option of a intelligent vapour membranes as well (it allows vapour in or out based on the quantity)
Why add the Blue Seal rubber membrane to the exterior if you already have the (zip system) plywood? Thank You for your help
I think it is one or the other. With the blue seal having a higher vapor perm rating 30 vs 15ish for the zip
Awesome walk thru. Best; Tom
@ASIRIDesigns - could you use a Zip assembly with 1" of closed cell spray foam on the interior side of the sheathing to avoid mold/rot issues (or potentially Zip R without the need for spray foam)? This 1" of closed cell would act as a vapor/air barrier and not allow moisture to condense on the backside of the sheathing, and would be installed prior to the cellulose dense pack...or would this create other unforeseen issues if you were in say a zone 4 climate?
My house is 50 years old. I plan to change the outer wood panels next summer. I also like to improve the insulation with rockwool and better vapour retarders. Do you think I can put in new vapour retarders without removing the internal drywall(gypsum board)? Can I just put the vapour retarder at the cavities and tape it well on the studs? Thanks.
What about fire block requirements? Do you need to do anything else? What about tall walls? Can I use this with stucco?
Tall walls need fire blocking (larger than 8 foot). Wide walls would need vertical fire blocking in those utility cavities.
What about doing all this but with a continuous top and bottom plate of either 2x8, 2x10, or 2x12 for both strength and simplicity? Also if you shouldn't overlap stud positions even if they don't touch in order to minimize thermal bridging, how do you handle the structural integrity of the corners of the house while also having a place for the sheathing, both interior and exterior, to attach at those points? Also, can you add Zip-R to either method or is that not cost-effective?
Lastly, can you do this with 2x3 studs on a 2x6 plate for the interior walls in order to maximize sound deadening on a budget without making hugely thick walls, or are there better options, especially for the 20-80hz range, which, to my knowledge, no conventional sound damping method can really control?
PS, have you heard about aerosolized caulk treatment for air sealing? They pressurize your house with a fan like the blower door test, then set off canisters of aerosolized caulk which will find gaps up to 3/8 thick/dia and seal them up. Ideally, this would be done after all the framing, sheathing, windows, doors, and MEP rough-ins/penetrations are complete, but before the insulation, interior sheathing, and final exterior cladding or outsulation are done.
Great video. I have a brick veneer 100mm cavity, 75mm stud walls with Gyprock interior sheet walls. How's best way to insulate these walls? Will blow in cellulose works?
Wow, the details are exactly the same as our company. I enjoyed the video. May you prosper. thank you
Great video on explaining double wall construction. I plan on doing this on a future cabin build.
I'd like to add rockwool to the exterior with a cement board exterior for improving fire resistance. What product do you recommend using to attach/support the exterior cement exterior finishing ? I don't want to use a lumber product due to potential heat transfer & damage from a forest fire. Thx.
PS: What is your profession ?
Amazing information and presentation. You helped me to understand a couple B.S. concepts i've been curious about for a while. I've been building with an emphasis on exterior permeability for a few years now. But what happens if you go to all the trouble to make the interior permeable, and then paint over it with a plastic (Acrylic latex) paint? It cuts off all permeability through the drywall, no? I personally like mineral-based paints, but that's certainly not the standard. Thanks again!
really good info, thanks for posting this, My qustion is why would you not use the zip sheathing system on the double stud wall?
I believe it comes down to the better vapor perm rating for the ply wood ~30 and 15 perm for zip
@@johcoppola thanks!
So even if im using zips board i still need the VP100 air barrier? 😊 thanks
Incredible content! Thanks so much.
Fantastic video and I love the building science, however cost to benefit is a concern.
If I build a house that I heat w a candle (net zero) vs a non insulated house that breathes well w no drawbacks other than heating cost.
My cheap 100k stick home costs me $200 per month to heat over 30y is roughly 8k and the savings wouldn’t cover the insulation let alone health concerns.
We can still do better.
I live in central Texas. Winters are mild and summers usually have 30+ days of 100 degrees or more. What would be the difference on how the wall is as it goes with interior wall design.......
thanks for the great vidoe! How are the 2x3 furring strips installed without compromising the smart vapor retarder?
Great video. I appreciate the detailed wall assembly diagrams. The pace, visuals, explanations, all good.
Question: Do you use standard sized outlet boxes or a smaller box to fit into the service cavity depth?
Wonderful video and amazing diagrams. Very clear and simple to understand. How does using something like Zip R-9 and 2x6 wall compare to a double wall assembly? Do you have a sense of where it would be as cost comparison?
Very informative video. I could be mistaken, but I thought it was recommended to use real plywood when is comes to sheathing since it has faster drying time in the event it gets wet. If so, wouldn't that rule out using ZIP system sheathing since it is OSB covered with a fluid air barrier?
I wonder what the cost breakdown comes out to be if you're doing a retrofit? I'd imagine throwing on exterior insulation and re cladding is going to be the winner in that case.
Can you do a video on post frame homes insulation and vapor barriers
I'm so glad I stumbled upon this video. Consise, up to the point and covering all details. Subsribed. One note- the l double stud wall will be more labor intensive, would be nice to get a rough idea of increase in man hours.
How would I hang stuff like kitchen cabinet on the drywall + 2*3 horizontal furring? I feel the 2 inch thick furring is not thick enough to hang kitchen cabinet. Also would it be a problem if some of the screw mistakenly break the smart vapor retarder?
The comparison of the zip and 2x6 to the blue and 2x4 double leaves me wondering about a mix of the two. Double wall with zip and Roxul insulated. I’ m all in for the non poly vapour barrier, but wondering what the benefits are to the ply and blue over zip if both are vapour retardant?
The blue and ply have a high perm rating 30vs15 for zip
How about 2x4 covered by 3" tight foam board then the covering, and drywall inside (with or without blown insulation)
could you do 1 for shipping container homes please
mold vs warmth vs cooling vs lost space
Great video!!! Very informative. I wonder if you can do a similar video taking into account the cost of labor (even if it's just the cost of labor in your immediate area, just for comparison) and compare the single wall with exterior insulation, to this double wall system, to a SIP wall system, ICFs systems and perhaps even a HempCrete with Just BioFiber System. Even if you didn't go into all the details as thorough as what this video has, it would be tremendously informative for anyone looking to build a new house to see what the ACTUAL cost of a wall system per square foot is. Again, even if you compare it only in your area, at least, people can gauge apples to apples in one area. They can just do calculations for their areas afterwards.
Thankyou for the video, it is very helpful
Awesome video, I was curious the difference between using a separate ply and air barrier for sheathing on the exterior wall instead of using zip sheathing?
Thank you - Simply put, plywood has a significantly better drying potential compared to OSB, as plywood can become up to seven times more permeable when it gets "wet", whereas OSB does not. The self-adhered membrane is also more vapor open than the coating on the ZIP sheathing. When it comes to these super insulated walls, it's crucial that they have the ability to dry out if/when they get wet.
Have you done one on tilt-wall?