Exterior insulation on foundation wall

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?)

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.

Well, take a look at that now.

There's a really big hole on top of the foundation right now too.

If building from scratch what's wrong with insulation on inside of block wall?

Insulation on both sides seems like it would be an issue like double vapor barriers.

You can't do that, you trap moisture / water.

I guess you could do fiberglass / wool without a vapor barrier.

AI told you you could use closed cell spray foam to prevent moisture from being trapped.

That kind of proves it's completely wrong, doesn't it?

Correct.

But the interior is where it should be "venting" moisture towards.

The outside is sealed via styrofoamfoam, caulk, tape etc.

You can't put a moisture / vapor barrier on the outside and inside.

I think so, yeah.

Hi, I'd like to see the concrete able to dry, if just because it might prevent or slow rusting of the rebar in it.

Yours, Larry

Hi, There's a whole lot of physics going on! You insulated the exterior, so the concrete will warm some. This will speed evaporation from the interior. Water has to be wicked up from footer to foundation faster than it evaporates for the concrete to stay wet. With luck it will dry faster than it takes up water.

I'm talking very long term in thinking about evidence of rust damage. Spalling happens when the rebar is close to the surface of the concrete, but yours is inside of the block. There should be little or no salt in the mix, so nothing to speed rusting. Spalling is more common in coastal areas. I just like to build in a way that can last and remain functional for hundreds, not tens of years. I've never been a "lipstick flipper" type.😉

Yours, Larry

Doesn't it take a month for concrete to get to 80% strength?

125 years for the Hoover Dam to fully cure. The embedded piping reduced the time a bit

500 miles of pipe in the dam.

Just tell me they threaded it all by hand LOL.

Wonder if it was leak tested😂😂😂😂