Where Design Meets Building Science.
Building science is the broader understanding of how architecture is intertwined with applied physics, engineering, chemistry, and health, in order to create durable, safe, comfortable, and healthful buildings that will last for many generations. Every aesthetic decision has technical implications, and every technical decision has aesthetic implications. Oftentimes, we use building science principles to address problems in existing structures, such as water damage and rot, mold, condensation, and poor indoor air quality. I make videos about how to prevent, mitigate, and address these types of failures in common building assemblies in the design phase, and how this approach should be integrated into the design process.
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Or, do all foundations with icf
Yeah, excluding the labor costs. That will be driven up significantly with all the different systems to work together.
I don’t do building or anything connected, cool vid but like why did i even watch it XD
Can you put fluid barrier (cat 5) over top of zip wall sheathing? I live in hurricane alley. Trying to go above and beyond.
You say that a vapor barrier is not needed if you have exterior insulation but, you don't mention how much that exterior insulation would need to be for either the wall or roof assembly.
Question: I live in the DFW area of Texas. I have a brand new shed I’m building, with 2x4 framing with ZipWall sheathing on the outside. I plan on installing Hardie cement lap siding with a rain screen/gap behind the siding. On the inside of the tool shed, I’m planning on applying a closed cell spray foam insulation, and then a moisture resistant drywall. The question is there any problem with applying a closed cell spray foam insulation in the stud cavities? The tool shed is not air conditioned, but I may put a portable unit out there for when I might want to work out in the 120 sq. ft. shed. I have made a couple KZread videos so far on the concrete foundation with a 6 mil vapor barrier, and the framing of the shed so far, in case you want to see what I’m working on. I have also made a video on the Froth Pak 200 spray foam insulation kit. Probably like most people, I’m not an expert on what to do with vapor barriers. Totally used to batt insulation. I’m a remodeling contractor for 26 years. What would your advice be for my climate zone?
Been watching this and some of your other videos addressing vapor barrier issues/questions. Great explanations! I have an odd situation that I'm struggling to figure out: I need to enclose a porch with a 2' high brick knee-wall, brick pillars at the corners. The homeowner wants to lose as little square footage as possible, so we were thinking have the drywall against the inside face of the brick, with the framing inline on top. How do I manage insulation and vapor control, though, especially with such a porous substance as brick (climate zone 4, for reference)? I'm thinking taped foam panels (maybe ½") between the brick and drywall, then transitioning to the regular framing, OR a smart retarder like Certainteed MemBrain. Would either of those work?
I would suggest to extend the outside wall insulation past the top of the foundation. The foam sill gasket is still a thermal break that could be covered
This is very interesting. I did not know that you don’t need siga majrex for your building if you install exterior insulation. Would it still be a good idea to install the siga majrex just in case the wall cavity does get vapor in it? Could you elaborate more on this please? Great video!
New Construction foundation concrete floor has visqueen (plastic sheeting) placed on floor before poring concrete and walls are of foundation have thick layer of more visqueen wrapped around outside walls sometimes repeating the steps. That is Building code (for decades) where I live also keeps moisture from entering past visqueen, Tar may not be enough.
I would definitely be interested in a video explaining the issues with airtight gypsum!
What is the reason behind gravel under the XPS plates that are NOT under the building? Reduced capillary suction or other? Can it just be groud?
Personally I would avoid using borat salts indoors because they´re considered to be an endocrine disruptor, IE messes with your hormones. Other than that I think most of the solutions are good/sound. People often forget that the biggest energy leak is when your building is not air tight. Just making it air tight helps a lot! Insulating should come as the secondary solutions because, as you mentioned, it comes with a lot of potential moisture issues.
Can a person put the seal then dimple mat/alternative on the outside, then insulate and side over that to keep moisture off the walls and not lose interior space if you are in a place like Florida for example. ...
Idk if it's really worth all of that. 2in of closed cell is 90% efficient. Then you don't need to worry about the condensation etc. 1in is 86%, 2in 90%, then you have to shoot all the way to 4in to get 92%. I am seriously thinking about 2in with zip sheets
Im here because a client of mine, has a hot water recirculating pump and the copper pipes in the slab are not sleeved, and only 4 inches below in the slab, the heat produced from the pipes were over sweating causing the wood floors to cup and separate, we jackhammered 500 sq feet and the ground was soaked under the slab. What a mess!
I'm wanting to build a storage pod in my back yard for a SeaDoo, which would be heated. What would be the best barrier? It would just be left open in the summer months because the Sea Doo will be at the lake. Hints? I could add a dehumidifier as well.
I'm glad you confirmed how I did my basement insulation lol, I copied Joe's system!
If you buy a new home save money on the initial purchase by leaving your basement undeveloped this will give you a chance to see what state your foundation walls are in by the end of construction.. seen some pretty large cracks in the past that just get covered up . If you have walls that are not in the mechanical room covered up and the rest are bare I would tear that out to make sure the builder wasn't trying to hide something... Just a friendly tip..
Put the framing a half inch or so away from the concrete walls. Put fiberglass insulation in, with paper-backing already on. Then stapled clear, plastic vapor-barrier to the framed walls - but only to the below grade height (of the outside dirt). 30 years & counting with zero problems.
Wouldn’t that create a tone of air and moisture penetration?
@@robertt9342 In the summer, we have a little de-humidifier on, like we did even before finishing the basement. No problems here, knocking on wood!
why do you need to be more vapor open the higher your wall R value is? wouldnt one vapor permeance value suffice as long as the ratio of continuous to internal insulation is the same?
Ive been questioning this for many years. Concrete walls could sweat and therefore a plastic barrier would not let the insulated wall breathe behind the drywall
thank you, love the new Q&A format with in-depth analysis of the control layers
Mold food, yum
I have a tricky situation and not sure which way I am going to finish my basement. New build just block foundation in Ontario Canada. High water table noticed very humid in basement and had some water come in from footings due to high water table. Outside foundation is blue skinned and xps foamed. We opted to go an interior french drain system with dimple board on interior walls into drain and seperate sump. On top of that we used roxul comfortboard over the dimplex and studded wall in front of that with roxul insulation. Rim joists are spray foamed. I feel like I would create a double Vapor barrier if I added a Vapor barrier on the studded wall and trap in moisture. Or do nothing and the dimplex sheet will condense in winter when warm indoor air hits it. I’m torn
I'm in Ontario Canada and have a very old home but lots of character so not ready to teardown. The exterior is currently lath and plaster. I can make shiplap concrete slabs to reclad the exterior. Thinking of putting xps foam on exterior then strapping then the tiles. What should do with the roof? Do I close all the soffits and do the same foam and new sheathing and roof? If so should I gap the new sheathing from the foam? Also how thick should I go on walls and roof? I can send pics if that helps. Much thanks
I'm building a house in very humid coastal region in Canada. Doing 2" taped rigid on exterior, 2x6 wall, batts in cavities, and gypsum board with paint. Debating using zip for exterior sheathing, or a plywood with blue skin WRB. Any suggestions would be helpful. Also what vapor barrier for interior? Thanks
Hi there, I’m building my house in Victoria. Just curious why not use a mineral wool for exterior insulation? Sleggs has a new product that is not Rockwool, stiffer and cheaper but same performance specs. If you are using a vapour barrier interior you might be ending up with a double vapour barrier situation and your walls will have trouble drying out.
I've never seen anyone in this area. Use the mineral wool and I am doing most of the construction myself and it seems it's harder to do the mineral wool. As far as the dryimg that's why I'm looking for suggestions
I love your channel. I’m renovating a mid century wood framed house on the barrier island Long Beach NY. It has a vented cinder block crawl space with 1’ above grade and 2’ under, with a rat slab. Due to a high water table, it’s frequently filled with water after a storm. I haven’t seen you post anything that addresses retrofitting for this condition. I was thinking to convert it to conditioned space by sealing off the vents, and adding a sump pump, but I’m interested in your ideas on how to deal with the groundwater.
Really enjoyed the Q&A, very informative, thanks!
I enjoy this and well as the more in-depth dives on specific topics. Quick Q&As allow for a more engagement with the audience. Both have value and you'll gave to find the ever shifting 'goldilocks' range that works for you, your community, and your team's passions and capabilities(and other factors and opportunities I may be missing.)
Thank you for your info on a very confusing topic, from Vancouver Canada. Wet, Cold, Hot, very high humidity. The go to around here seems to be Tyvec but I think that is because most builders in this area do not know or care, it is all about making big bucks. A very sad situation for the consumor/homebuyer
Thanks so much for covering this subject matter. I am in the PNW, Lower Columbia/Astoria area and in process of new home design. I reviewed your article from Sept 2022 '5 High Perf Wall Assemblies for the PNW Climate'. Once I get my design completed and better understand my budget, if I can afford the top end assembly I will go for that; or will adjust back to option #1 if I need to conserve costs ;) ... very good stuff!
We see a lot of joist pockets with problems with trapping moisture.
Love all of your videos, they are very informative! Other than of course cost, why did you think many people seem so resistant to exterior insulation? Are the details/trades operations really that challenging to get it done right?
Great video. Answered some things I have been wondering.
Love the Q&A format. Keep them coming.
Question .. Should the groove for the exterior horizontal tongue and groove cladding face up or down? I'd say up if water leaves by evaporation and down if it leaves by draining. Asking as I've always wondered and I see it's facing upwards in the drawing at 1:41. Thanks!
YEP! Good catch, looks like the profile got flipped.
Can you consult in Canada?
*Time stamps for anyone who's interested* 0:16 ZIP System in Double Walls vs Plywood 2:08 Basement Walls with Housewrap and a Vapor Barrier 3:58 Do Smart Vapor Retarders Really Work? What is the Cheapest Vapor Retarder? 7:23 Why Not Always Use a Vapor Open Air Barrier? 9:31 Insulating an Old Farmhouse
Excellent video packed with a lot of fast moving information. Would appreciate more detailed videos on each subject with pros, cons, good, better and best examples. Love your videos and thanks for sharing. 😁👍
Love the content. What about hot Arizona climate, with cold air conditioned interiors, whats the ideal wall assembly?
Thank you so much. Because much of AZ is a hot/dry climate, there is a lot more "forgiveness" since things dry out. If I was building my home in Phoenix for example, my wall assembly would probably look something like a reinforced CMU block wall with a fluid applied water and air control layer, a couple of inches of polyisocyanurate installed outboard, and some stone veneer with an air gap. You get the benefits of a thermal mass to keep the building cooler, and the rigid insulation outboard will make sure that you slow any heat transfer (you could also use ICFs if this was cost prohibitive). Big over hangs and north facing windows if possible to reduce heat gain.
Would love a video(s) going over the mechanical and/or passive ventilation that is needed when we are retrofitting to a more air tight assembly and how that may differ by climate. I am in zone 2 and I see so much focus on the wall/roof details but not as much on the makeup air and keeping humidity levels controlled with an HVAC systems that is going to be running less in the more mild months. With a retrofit on a budget where someone is just doing siding, insulation, air sealing, and windows, when do you need to consider makeup air? With unlimited budget one could do an ERV + dehumidifier + swap out to a smaller HVAC system, but there has to be some more cost effective or DIY options.
I would like to hear your thoughts on this too
This is a really important topic that I've briefly mentioned in past videos, and I certainly plan on addressing this soon. In my opinion, you always need to provide make up air if you're exhausting at a rate that places your building under negative pressures, it's non-negotiable, but the challenge is providing make up air at the right rate without increasing interior relative humidity levels in zone 2, and as you suggested you need additional dehumidification. Look at an ERV and a dehumidifier as something that must be included in part of the budget, these are essential systems. When you improve energy efficiency in a humid cooling dominated climate, you get rid of all of the incidental dehumidification benefits provided by the air conditioning since the A/C isn't running nearly as often. Have you watched these videos of mine?: kzread.info/dash/bejne/Y4iptK1sc6ydmsY.html
@@ASIRIDesigns How about making a video series/ playlist broken down for each climate zone? That way everyone can get their questions answered for each climate zone? Thumbnail idea: picture of that part of the U.S., etc and then Climate Zone # written over the picture. Most people don’t know or have memorized what climate zone they are in, so maybe write something like Central Texas and Climate Zone. By doing this you could also reuse the same video editing, but maybe change some of the voice over, so it seems like it’s customized to each state, region, etc.
Should I insulate an unconditioned accessory building? With the extreme heat and sometimes freezing cold climate of North Central Texas, I am planning on insulating my tool shed with closed cell spray foam, and making a KZread video about it. I like the idea of doing everything I can while I have the walls open for insulation, wiring, etc. rather than trying to go as cheap as possible. Hopefully this shed will help protect my tools as much as possible from the weather, moisture/vapor, etc. considering there won’t be any regular air conditioning. Just wanted to check with you first to see if closed cell foam was a good/bad idea.
Do you recommend taped rigid insulation for wood foundations?
Ive got a 1940 house with oak sheathing, i planned to have Rockwool in the interior cavity but on the outside wall ive been thinking wrap tyvek and add 1" foil faced eps before my vinyl siding. Is the tyvek a problem sandwiched between the sheathing and eps? Is the eps too thin in this situation to cause more harm than good?
Mid missouri climate,
This video answered all my questions I still had about vapor barriers. Awesome!
So glad to hear it! Anything else you want to see in the future?
very curious what you would say about buildling in tropical climates, where all the cooling is internal, and windows are often open for much of the day, and there's lots of humidity! i'm guessing the only option there is external insulation?
Yep! You guessed it, external rigid insulation, preferably rigid foam unless you're dealing with termites, and something to slow inwardly driven moisture installed on the outside (this could be the rigid foam itself, or a semi-permeable WRB). Wholehouse dehumidifiers are a necessity if you're opening windows. Also, non-paper faced interior finishes, as these have a higher potential to support mold growth in these climates. If you're installing drywall, I'd use fiberglass mat gypsum like Densarmor instead. Absolutely no interior vapor barriers or vapor retarders.
@@ASIRIDesigns awesome. thank you very much!!
actually wait. why a semi permeable WRB? something non permeable like aluminaflash not a good option?
this is great! thank you
I think the problem that most people have with regards to vapor and condensation is trying to understand how it migrates, where it condenses (which side) and its relationship to climate both internal and external. Once people understand that, all your strategies make way more sense than the simple “how do I insulate”
what is a good video or website to understand this?
@@finmlpal7370 That’s just it, if ASiRI is doing Q&A, this is a good topic for him to dive deeper into.
Great point, we might need to do a general crash course at some point.
@@finmlpal7370 Check out the articles over at Building Science Corporation, namely this one: buildingscience.com/documents/digests/bsd-106-understanding-vapor-barriers
Thank you!
Thanks for watching!
would it be possible to pair a brick facade with a double wall assembly?
Probably not the best idea, but it's certainly possible. I'd use a thin brick installed over something like Dorken's Dry and Lath dimple mat product so that the reservoir cladding is completely uncoupled from the double wall. I don't want to challenge that double wall system in any way that could result in additional moisture accumulation.