Foundation Wall – Interior Insulation – XPS ‘and’ Spray Foam
Climate Zone 6
On the interior side of foundation wall (wall below grade), I have 2 inches of XPS (the blue stuff) between the studs. Is this ‘good enough’ even though it is not a vapor or air barrier, or should have another inch or two spray foam in addition, or some other material, like batts? No worries, not going to use any plastic vapor barrier on inside.
How about on the inside of the exterior walls only at the rim joists (2×6 wood stud plus zip sheathing). These areas also have 2 inches of XPS so are not spray foamed at the moment. The other parts of the exterior wall will have 2 inch spray foam and xx inches of fiberglass batts. In the planning stage, I wanted all insulation to be spray foam.
In other words, is it better to have spray foam on top of blue foam vs. only blue foam (I know it’s more expensive)
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