Insulating Exterior Walls without Sheathing (from interior)
The task of this week is overhauling a bedroom that is adjacent to a busy road. Sound and temperature swings are issue in this room, despite new windows, due to a lack of insulation.
The house is a 1950’s single family home, Climate zone 4 (marine – San Diego). West facing exterior of the room is stucco over lath and tar paper, 2×4 framing with no insulation. The side of the room facing the busy road is wood siding over tar paper, 2×4 framing w/ no insulation
The project is to remove the 1/2 inch gypsum and insulate from the interior. I will pay particular attention to airsealing the cavity before insulation begins.
I plan to use 3/4 inch furring strips to provide an airgap to the exterior siding followed by:
-R5 Sika Rmax Pro (poly iso foam 1inch thick with aluminum facing)
-R15 Rockwool Mineral Wool
-Reslient sound Genie Clips + horizonal hat channels
-Doubled 5/8 gypsum with green glue
My main question is should I remove the aluminum facing on the polyiso to allow for interior drying? I am having trouble finding 1 inch XPS, so this is my next best option.
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