Exterior insulation on foundation wall

ethicalpaul

@hot_rod said:

pretty much any detail you see on a stucco building is foam, with the stucco over it.
Here in Utah the on/ off ramps are built with foam blocks, paved over.

it’s almost as if the whole thing isn’t a big deal at all!! 😅

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1894818#Comment_1894818

It's not rated for ground contact

PC7060

https://forum.heatinghelp.com/discussion/comment/1894818#Comment_1894818

It’s a nice product. I’ve used Densglass to build up architectural details. It’s often used under the stucco / foam layer for commercial builds.

TAG

NJ has had a separate "energy code" as part of the the building permit for over 20 years. I had to do one back in the mid 00's and not a couple years earlier.

Continuous exterior insulation is not required in NJ. You can do it but it is not required. Lots of ways to meet the requirements

I know from experience that the biggest energy loss in a basement is going to be those few feet out of the ground. If the building is framed above the foundation — air leaking is often a larger problem vs any insulation. Very few contractors spend much time other than rolling out some thin foam. IMO — it's not thick enough even when the top of the masonry is relatively flat to seal the top plate. Most of my early projects were in NJ including a block/ brick faced house from the 50's that I made into my first home/ office. It was a large house with a huge full basement that allowed 1/2 to become my office. There was no air leaking into the basement — when we did the heat load calculations adding only R13 the numbers were so low I had to check them a couple of times. The big problem with basements is water. The basement floor in that building was not cold because the soil under it was dry. Water changes everything especially if you are trying to heat the slab.

IMO — 2x6 walls w/ closed cell foam and plywood sheathing. Good windows and 5/8 rock. Most of my projects have been restorations with additions and I have given up on wood for the additions other than the windows and it's trim. Closed foam stops air leaking — you need to understand it's use in an old building — it's a real problem solver.

Foam under stucco has a long history and one with no shortage of problems. Buildings leak — best have a way for them to dry. Especially when you create two vapor barriers. Look how long they pushed plastic VB for energy savings — how many walls rotted away in cold climates? This can be a problem in roof structures if the wrong ice and water shield is used all over a roof deck (more is better — right?)

TAG

https://forum.heatinghelp.com/discussion/comment/1894579#Comment_1894579

Panel roof construction is all about the same — typically osb and some type of foam w/ 2x material on the sides and ends — make sure you follow the manufacturers recommendations to the letter. Especially the internal sealing of the panel joints to the heated space.

Kaos

https://forum.heatinghelp.com/discussion/comment/1894928#Comment_1894928

If you look at most of the spray foam, it gets applied to places where air doesn't leak like directly over OSB panels and it doesn't cover some of the big leaks like wall corners and foundation/wall joint.

You can get much better air seal with a couple of rolls of fancy tape (ie Zip or 3M8067) and an hour or two of elbow grease by taping all outside seams. It is THE easiest/cheapest enegy improvement one can make.

This avoids the cost of spray foam plus the risk of a bad spray foam job (~1%, remediation is impossible without demoing) .

Your insulation dollars are better spend on getting high density batts which give you a small R value bump plus much easier to get a grade one install.

Spray foam is definitely great when dealing with old structures and rubble foundation basements. For new construction/addition, gets you nothing.

ChrisJ

I'm not sure if it's been mentioned or not, but one of the benefits of my leaky basement is there's never a shortage of combustion air.

Or a breeze for that matter.

@ethicalpaul Have you considered how you're going to bring in combustion air for your boiler after all of this is complete? Knowing you, you did months ago.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1894937#Comment_1894937

This addition on its own will in fact reduce the air intrusion through the old wood plank door (under the Bilco) that was at the rear of the basement. This is where the addition is going. And I assume the new basement door (I'm keeping the Bilco door, but in the addition part) will be much more airtight than the old one. So the change in available combustion air is a concern.

Luckily, I have an old dryer vent port near the boiler from when the washer and dryer was down there that I can re-purpose into a combustion air vent.