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Community and Q&A

Insulating exterior walls

rvitelli4 | Posted in Energy Efficiency and Durability on

Recently gutted out the walls of a 1942 house I just bought in Ohio. My question is what kind of insulation would be best? It’s plywood sheathing and aluminum siding. I was thinking of sealing all the gaps and studs with ‘great stuff’ and using batt insulation. Any potential problems doing this on an old house with no housewrap? Maybe closed cell foam is the way to go even though I’ll get a lower R-value, but is that pain for electrical work?

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  1. GBA Editor
    Peter Yost | | #1

    With the exterior wall framing cavities open, you should do a thorough inspection for moisture: water stains, "punky" spots, mold/mildew to determine if your wall is moisture-managed without a water-resistive barrier (WRB). Don't insulate at all until you have water-managed the wall.

    Next up after bulk water management is air sealing. Use the Energy Star Thermal Bypass Checklist to prioritize your air sealing efforts. Could be your best bet for a continuous air barrier is when you re-sheath the interior of your exterior walls.

    THEN, pick a cavity insulation; the options are too numerous to cover in Q&A; maybe start your consideration here:


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