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1920 basement/foundation wall repair

rhl_ | Posted in General Questions on

Hi, i have an old house, with 1920 era fieldstone foundation walls. They were painted with white paint (im guessing drylok), and in some places some form of concrete/stucco/who knows was used to flatten them, then again white paint on top.

The walls have had moisture issues. We have had the exterior walls waterproofed in all but one section (below the patio), so where possible all walls now have exterior footing drains, installed to GBA standards, waterproofing, exterior rigid insulation, plastic vapor barrier — the works. We also have interior footing drains in the whole basement. We had the ceiling open, we airsealed/insulated the rim joists.

I now want to _repair_ the damaged walls, remove all the peeling paint, apply X to make the walls approximately flat where possible and then after we see that it stays dry for some time, add interior rigid insulation + drywall (likely with dricore smartwall).

The question is what is X. Is it concrete/stucco/something else?

When we did the rim joists we removed a small bit of the top of the foundation wall with a chipping gun. (in order to bring HFO foam into the cavity). We repaired that recently with “structolite.” How does that compare to concrete/stucco? It advertises being insulative.

If we use stucco i’m guessing we need a wire mesh in order for it to bond to the existing wall?

Any advice here would be appreciated.

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  1. Expert Member

    That's a lot of nice work!

    A picture is probably worth a thousand words, but if I were in your shoes -

    1. It's going to be nearly impossible to remove the paint from the way in a say that's thorough, easy, mess free, and cheap. If the walls are now waterproofed as you say, you probably wont have any further moisture ingress from there. I'd wirewheel away the parts that are easy to get, and shopvac everything out.

    2. If it's 1920's and later, it's most likely cement based, mortar, stucco, or whatever, its all really just a 1:3 cementacous material / sand mix. If it's stuck on well, I'd just leave it, unless it's protruding.

    3. The Structolite is a plaster made from gypsum and perlite, and probably shouldn't get wet. It's fine to use, however, if you're reasonably sure that the water problems are fixed. I wouldn't count on it to insulate, but it is pretty easy to work with. I'd apply a good bonding agent over the wall, and use a self furring wire mesh with it to make sure it bonded well and was strong, and then you can do as you wish with the rest of the interior. Structolite is not as strong as a pure cement based product, but it's probably plenty strong enough to fill in the gaps.

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