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Rim joist retro insulation with spray foam?

15 years ago

My '80's British Columbia house has insulation stuffed into the basement rim joists, but I don't think there's moisture/air barrier over it in all places, from what I can see. What I have been able to get to has black discolouring on the insulation I guess possibly mould, or just moisture? We have a very dry climate here, humidity rarely gets over the mid-30's even in summer.

I am assuming this was permissible code in the day, or the basement was finished later, amateurishly, as much of the work seems to be - there are no substantial moisture issues but they have messed up in places, I'm slowly fixing it.

My question is this: It's not practical to redo the rim joist insulation everywhere, but where I CAN get to it, is sprayfoam in a can a better alternative to fibreglass and plastic? I know if I don't do it all, it's not very effective but there are places like a plenum where pipes etc enter I will be cutting an access to, because we will be running wires and a/c plumbing through. I figured this is an important area to redo since the pipes/wires will conduct cold in.

I am assuming "greatstuff" the non-door/window stuff in small quantities is the way to go, and it's an equivalent to the commercially sprayed stuff?

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