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I’ve been thinking about exterior insulation. Why do people always want waterproofing on the home and the exterior insulation? Easier for walls, where do you install the WRB? I always go over the exterior insulation. It’ll stop it from getting wet, as well as from having air movement through it. For a basement wall maybe not as easy. But still exterior insulation, then your dimple mat etc, keep the insualtion dry and performing as it should. Now how to tie that up to siding? Maybe a hydraulic cement parging? That way exterior insulation can continue from basement up to the siding system? Dimple mat below grade outside of insualtion, then hydraulic cement protecting it above grade foundation, and then siding covering, and WRB covering insulation on exterior walls. Any insight on this? I know there’s a lot of systems that do basement waterproof and insulation. I take from the classic CI and WRB (which goes first) argument and bring it below grade to see how that can be done.

Thank you

Looking at an in-wall ductless ERV for our tiny house build. They recommend buying a pair. Do you think this is best or overkill for a tinyhome?

I wonder if there are cases where decades of farts from a rec room are trapped in the vapor barrier?

I’ve got to watch this sober. I think it’s important for my off grid cabin

You guys killed it on this video. Thank you.

And this is how they built the International Space Station... For houses, try something a little simpler.

4:01 This is changing in Quebec, the APCHQ has tested the so-called perfect wall with outside insulation. I believe they are currently pushing to change the industry standard to this method. Exciting times!

Trapping water against any surface can lead to disaster. Materials like chip board/beams/ibeams, drywall even concrete can eventually rot away. Here, try this next untested materiel or method. Getting old.

Plants in the house do the same thing. What kinda yuppy crap is this? Im sure some dumbass with money will buy it.

With the use of furring strips, you only need two fasteners with washers to hold the rock wool boards in place during assembly. But how do you hit the studs when going through furring strip, many inches of insulation (more than 4" for an off-grid optimized home!) and a drainage layer against sheathing, then the sheathing? This problem is particularly of concern with roofs, since the insulation is typically thicker! Also, where the heck do you find the screws needed for these thicker assemblies? So far, the best I've come up with are screws designed for assembly of SIP panels. Finally, how thick of a layer of rock wool do you need to provide the advantage of resistance to wild fires? What's the spacing of screws needed on the furring strips so your metal roof or siding doesn't rip off?

What’s the point of the rainscreen with a high permeable insulation like rock board? How do you address the rain screen in fire country if the strapping or siding is flammable?

BS + BS

Note that the energy codes in my area (NY) allows GWB to act as the air barrier. High humidity areas should be vented and low perm paint. Additional sealing from conditioned spaces for mechanical and electrical penetrations. A practical approach but may not be 100% , but then you will not need to add fresh air exchanger.

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) ?

My house is 1925. The attic has close cell spray foam. The roof is about 5 years old. What can i do to prevent mold from developing? I run a dehumidifier in the attic and basement. Thanks in advance for your help.

Wow. All the basements I’ve seen here in Utah have insulation up against the concrete foundation and 90% of the time covered in plastic sheets. Ugh. 🎉

In a conditioned crawlspace, 99% of the new houses in my area have sump pumps due to a high water table. Add AC condensation drain lines and you have the entrance of direct moisture in the conditioned space. Is this acceptable or is it treated in some method?

I wanted to insulate the attic which has rigid vent but not soffit vents. What is the best insulation type in this case. I live in Massachusetts. I already started with one side and installed rafter vents, but I was thinking maybe would have been better and cheaper to install thermal bubble roll. My idea is to create a leaving space on the attic. What is the best choice in your opinion?

Just found your channel; super informative, thank you! I noticed most of the resources on your site seem to be aimed at professionals: would you consider creating something for homeowners? I am looking to insulate the attic (and maybe walls?) of my circa-1919 house in the upper midwest but I am worried about someone coming in and doing it wrong and causing some of these mold and condensation issues (and also realizing I already have those issues from summer AC use causing condensation in my walls most likely). I want to be able to understand what the best practice solution looks like so I can be confident I'm hiring someone who knows what they're doing. Thanks so much for all the great info!

Your exterior wall concrete curb is not wide enough to please the structural engineer.

How do you do an interior bearing wall with the slab & insulation on grade? Is it just like the exterior wall?

Is there any issues that you can see using newer synthetic underlayment? Not referring to ice and water shield that is applied at the eaves but the product that is applied to the rest or the roof deck. Every roofing manufacturer seems to have their own (IKO Stormshield, BP Suredeck...) but they are basically all the same and are mechanically fastened. There are some (ex GAF Deckarmour) that are marketed as breathable. Do you see these making a difference? Enjoy the channel and am getting more and more interested in building science.

Great video. Please get rid of the irritating music though.

Excellent video. One slight quibble: the graphic at 3:15 is not quite accurate as the air streams in an ERV don’t actually mix; they bypass each other in the ERV core transferring much of the heat and humidity from one air stream to the other. One could be even more precise about the exact science involved, but this is probably close enough for the purpose of this video. Thanks for the excellent content as always!

Your video early on includes the Techshield product. How do you explain videos like this one, which purports to show lower attic heating with the OSB bonded radiant barrier pointing in towards the attic space: th-cam.com/video/sUwl9CMtTqg/w-d-xo.html I am thinking there must be some reflective surface on the other side of this pointing into the OSB, and something there to create an airspace. I don't understand how this result could happen when the reflector is point away from the radiant heat to be reflected. It makes no sense at all. Yet they do a temperature measurement and the foil product does appear to drop the temperature.

Just curious what you think of evaporative coolers in dry climates. They are low energy consumption and effective most days through the summer.

Had this discussion the other day. Will be sharing your video. Thanks for the short simple explanation.

Is there any way to have a pretty well air sealed house and not bring In outside air while maintaining good indoor air quality? Some older houses are very hard to air seal to the point that you need an hrv or erv and I have to imagine there are ways to be healthy in those houses

Make a video about building in a sub Arctic rainforest like southeast Alaska

In western Canada it’s common to add humidifiers to natural gas or propane forced air furnaces. Mostly in older, non efficient homes. Otherwise the RH gets very low and can affect health and humidity sensitive objects like musical instruments. With a modern well insulated and sealed home would this be necessary? -34 C (-44C with wind chill) today. Not sure why I still live here in winter Lol.

I just finally finished getting my Broan HRV ducted and set up and man do I love it. I left it on intermittent while I was away for Christmas and when I got home the fresh Vermont air smell in the house was so pleasant! In addition to that experience, we no longer have condensation on the windows in the morning when we wake up, and the control is just outside the bathroom so you can put it on turbo on your way in to do whatever you’re doing in there. It much more noticeable than you think it will be when you have good air quality in the house.

Everything he states is so true. If people could understand and realize the benefits of building a tight home more would do it. They only care about the cost instead of the comfortability.

Do you have any experience with CERVs? ERV with integrated heat pump, which can heat, cool and dehumidify. There`s only two companies I found, Equinox and Minotair.

I'm surprised you didn't mention kitchen exhaust hoods and cooking fumes/vapor.

Between 40-60% humidity is where the least amount of growth is for molds and viruses.

Great info, i was just thinking of what would be the perfect wall !

Why do we want to make something necessary when all of human history it has not been? What could be some unintended consequences?

Great info, this answered my other quesiton

Very informative. I was contemplating installing a heat recovery unit but not a dehumidifier. Well timed. Thanks.

Liked#6 N Subscribed!!!

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'm always for the most simple designs. Energy efficiency is NOT my highest priority but total operating costs.

Do i still need something like typar or drain wrap if i just add the air gap?

How do you stop fire spread with perfect wall approach?

Question. What would be the cost difference for a Tyvek wrapped house vs a zip system? Any other options to reccomend? I know cost may be hard to say but just the roughest of guesstimate is fine. To add more info a local builder said all the framing for a 1227sqft house cost him 24k. Im assumingg thats house wrap, sheathing, and roofing because that isnt mentioned. No clue. Insulation was 3200 for basic fiber glass. Im starting a mentorship soon and the guy builds houses he sells for a little under 300k which is absurd in our market. Our median home price is like 430k. Homes the size he builds are usally around 350. Hes ranging 280 to 320k. With that said, he does skimp on materials from what I've seen. He's using homewrap, and I've even seen it fluttering in the wind on his IG posts. I want to do a bit better, but i still want to have the ability to service that same 300k customer because in all honesty, that's the level of home i'd buy with my own personal budget. I'll be getting his full list of sub contractors, lenders, and etc. I just want to do some slightly better stuff without totally changing the blueprint that allows him to profit with prices that low.

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 ?

Dry rot? There is no such thing.

A lot of variables seem to be in place here. Moisture in the concrete, both conditioned and unconditioned air, water table depth, etc. Adding a sump pump crock and moisture producing condensation line for AC in the basement all add up to a difficult at best potential issue.Trapped moisture seems to be the gorilla in the room. I'm of the KISS concept, and would try a formula using a HD Dehumidifier in the basement, no vapor barriers. I'd pump AC condensation and dehumidifier lines into the sump pump crock and use a secondary battery powered pump for utility power outages. Keep in mind, foundations typically have drains surrounding the basement, this is a very large amount moisture to contend with, especially in a high water table area. I learned a long time ago, it's a lost cause trying to prevent water.moisture entering a basement. The best efforts should be focused on moving the product, quickly and precisely where you want it to go.

The drainage design shown at 4:54 has two design mistakes that would be grounds to sue the builder here in Finland. The design at 2:31 is a good design with a couple small tweaks. I built a new house a couple years ago, I can send you the drawings via email if you want to see how we design and build new houses. In my opinion our designs are better than those shown here. It is interesting to see how it is done on the other side of the big pond for sure though, thanks for the video.