Questions on a “not-so-deep” retrofit…
1948 mid century/ranch, stucco exterior
Wood shaving insulation with paper face stapled to framing
2 layers of (I believe) “plasterboard” 3/8″ over 5/8″ = 1″ total
Kitchen renovation found no evidence of moisture in the ceiling or walls, removed wood shaving insulation and replaced with R-19 batt (regrettably but can’t undo now)
Polyethylene vapor barrier on interior side of renovated walls (insulation code official laughed when I said that I expected him to closely scrutinize the vapor barrier and he said, “There are so many holes in this old house [windows and doors], this renovation could have a perfect VB and it wouldn’t matter”)
Attic space had a layer of unfaced batt insulation over the wood (where I didn’t renovate. I sealed every penetration I could find with spray foam and I put vent chutes in almost all of the cavities and blew in 12″-15″ of loose cellulose so I feel like the attic is as good as I can do for the budget that I had. We removed an exterior door in the renovation and framed it in/insulated with the batt, re sheathed with plywood and threw some building paper on – 2 years have elapsed.
It’s time to fix the “hole.”
I want to do whatever I can within my meager budget to add insulation to the exterior and break the thermal bridge to the exterior and this hole will set the precedent for the way I’d like to do the rest of the house. I don’t know what to make of the 1″ of plasterboard and the wood shaving insulation in terms of moisture permeability from inside to outside but I do know that the walls are freezing. ASSUMING vapor is traveling to the exterior (a big if and I’d love to hear opinions)…
My first shot at the wall assembly is this (exterior to interior):
Siding (horizontal, likely thermally modified ash)
1x treated furring strips (attached with a Heco Topix screw [or sim] to 1 1/2″ sheathing/framing penetration)
Roxie CavityRock (layered up similar to a deep retro fit found on this site) Mono and Double Density as suggested for furring compression
Vaproshield (Wrapshield SA) self-adhered seems like it’d be easier to install but I’m listening to opinions.
Sheathing (existing if good)
Existing cavity insulation
Windows will probably have to be replacement windows and I’d be spray foaming the opening prior to install
It should be noted that this “hole” is in a 3′ -6″ porch and there is a 3′ eave/overhang on the house. The “hole” is on a wall perpendicular to the main facade. Almost no weather ever gets to this particular wall.
I’d greatly appreciate any comments/ideas.
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