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Best way to retrofit insulation in 2×4 stud walls

marku52 | Posted in Energy Efficiency and Durability on

Hi, we have just moved into a 1960’s home in Medford OR, zone 4C. Wow, after living in a passive solar well-insulated modern home, I had no idea life could be so uncomfortable in winter. I’m cold all the time because the walls are freezing.

So, walls are T111, 2X4 studs, no insulation. What is our best plan to get some insulation into the walls? We know that we need a lot more cellulose in the attic, but for now we have to put that off. Windows are modern Lo E, so that helps. Is it possible to spray foam a stud wall in place (after drilling holes, of course). Or is stripping off the interior drywall and doing a “Mooney wall” a better bet? At this time I am leaning more towards internal fixes than external. Of course, blowing in a lot of spray foam is easiest of all, but does it actually work? I’ve heard horror stories about blowing drywall panels off, bad chemical smells, incomplete fills, etc.

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  1. GBA Editor
    Martin Holladay | | #1

    The most cost-effective approach is to install dense-packed cellulose insulation between your studs. Because you have T-111 siding, which is hard to patch, the insulation contractor will need to drill holes through your drywall, and the holes will need to be patched. This work will be somewhat dusty and disruptive, and will require interior painting.

    In the future, if you ever decide to replace your siding, you can install rigid foam on the exterior side of the T-111, followed by vertical furring strips and new siding. But that work would be expensive.

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