Rim Joist Must Be Allowed to Dry to Inside?
Just looking at my above grade crawl space assembly in Southern Ontario.
There are no sill plates, rim joist only. I have cobbled rigid EPS foam, used foam adhesive to keep in place in rim joist spaces, and spray foamed around the perimeter of rigid foam on 3 sides so far. I will be spray foaming the bottom perimeter of the foam pieces and the underside of the rim joist soon.
The walls of the crawl are rigid and spray foamed too. Vapour barrier sits on the interior of the insulation on the walls, a few inches below the rim.
I’m wondering about the space between the wall and the rim, as well as the rim itself. I DO NOT vapour barrier this area, correct? Although concrete does not need to dry to the inside, the rim joist must have to opportunity to do so, right? I’m assuming that the rim joist can only dry through the EPS foam and not the spray foam?
The rim joist is 2 layers of 2x10s on 2 sides of my rectangular cottage, and 1 layer of 2×10 on 2 sides. The cottage is clad with wood ship lap siding.
I don’t have to worry about spray foam on the underside of the rim joist blocking the drying potential of the rim (in particular the outer layer), do I?
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