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How to insulate without rim joists?

10 years ago


So, we have a 1935 Cape Cod and (as some of you have seen) we're moving ahead on finishing our basement (much thanks to worthy for insulation guidance and pointers).

One of the regularly recommended steps is to insulate the rim joists. However, it seems that we don't have any.

Hopefully, you can see from the picture I'm including that, on one end of the house, there's a gap behind the joist closest to the cinder block wall. That cinder block continues up an inch or two behind the joist and is immediately topped by a brick-like material (sure looks like bricks but there seem to be some places where it's something that's brick-like, but hollow on the inside, like cinderblock but brick). There is nothing like a horizontal beam -- sill plate -- across the top of the foundation wall and there is no rim joist on top of that (as I've seen in pictures of modern houses on the web). By the way, this situation replicates itself at the 180-degree opposite end of the house.

Also, I hope you can see that at the end of that joist, where it goes into the wall, there is no rim joist there, either. This, of course, is the case for every parallel joist, from one end of the house to the other.

So, I'd been thinking that I'd use an expanding foam to seal the gap between the outermost joist and the parallel wall (though in some places that gap is two inches wide). Should I do that? What else could/should I do?

Similarly, what to do between the joists where they enter the wall at the far end?



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