Closed-cell spray foam versus dense-packed cellulose – Noise control in a PassivHaus
This is a comment rather than a question.
In our pre-certified PassivHaus in northern NJ, we have 10-inches of densepack cellulose and 2-inches EPS in the walls, and 10-inches of closed-cell spray foam in the roof.
We’ve noticed that the noise attenuation through the walls is much greater than through the roof.
Most of the noise getting into the attic comes through the roof, which is asphalt shingle over plywood decking on 2×12 rafters, with the space between the rafters filled with 10-inches of the closed-cell spray foam.
Lots less noise comes through the walls, which are double 2×4 frames on a 10-inch baseplate, covered with Zip-system sheathing, 2-inches of Type I EPS foam, and Certainteed Monogram vinyl siding.
If noise control is important to you, and you have a choice of insulation products, you might prefer the densepack cellulose over spray foam.
(We were told that we couldn’t use densepack cellulose in the roof due to building code restrictions.)
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