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Community and Q&A

Insulating old walls

jz613 | Posted in General Questions on

My home is a circa-1930 wood frame in NYC, with an extension that was probably added sometime in the 40’s. The extension appears to be double layer brick, with stucco on top on the exterior, and furring strips+plaster on the inside. The original structure is cement stucco, (rotted) roofing paper, tongue and groove panels for sheathing. Inside is plaster on lathe. There is currently zero insulation, and the walls are freezing in the winter. What’s the best way to insulate without gutting the house, and without having major moisture problems in the walls?

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  1. Expert Member
    DCcontrarian | | #1

    For the wood frame part look at blown in cellulose. For the brick extension there's not much you can do. Also look at the attic and basement.

    For the whole house air sealing is a good bet. It's minimally disruptive and not that expensive.

  2. user-1072251 | | #2

    Since the exterior finish has failed ("rotting"), its an excellent time to add exterior insulation under whatever finish you use. 2'" Plain Expanded polystyrene will work fine. Be careful of installing a non-permeable (One that doesn't let moisture through) as that may precipitate a mold problem.

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