Retrofit Balloon Frame Envelope
Greetings GBA community,
Our home is a beautiful onion. More layers than I’ve ever seen (no insulation except attic). 1880 balloon frame in Zone 6. Electrical issues have led to many interior areas of our home being opened up. It’s been a great opportunity to really get to know this home. Our budget is tight right now but priorities from the inside are fire blocking and air sealing everything I can get to without removing plaster/lathe. Sill plate is accessible inside basement and second floor ribbon area is reasonable to get to from above. I keep landing back at a necessity to address the envelope problems from the outside because of insulbric or similar product on the exterior. Am I missing a simpler more cost effective approach?
Panelling 2/3 layers over top of plaster and lathe walls (some places 3/8″ drywall between). The wall assembly has 1″ thick solid wood horizontal boards both inside and out of the true 2×4 studs 24″ oc. The ribbon board is not let into the studs on the second floor. Main floor joists sit on true 2×4 sill side nailed into studs. There is no capillary break between the stone foundation and the sill. Poured concrete is reinforcing the stone from the slab up to about 4′ which leaves 3′ of stone exposed above. Three layers of exterior siding products 1) insulbric 2) stucco with metal mesh and at least one layer of heavy weight tar paper 3) vinyl siding on 3/4″ vertical furring. Attic has something loose fill. Soffit appears vented but baffles if present seem compromised. Two whirly birds on top of metal roofing (1 maybe 2 layers of shingles under).
1) Is an interior air barrier a good investment for us?
2) Can I spray foam the rim band area without creating moisture problems (no capillary break between sill/stone foundation and necessary inward drying because of insulbric)?
3) Would it be necessary to remove insulbric to be able to blow insulation into the balloon frame walls?
4) Would adding an interior wall to gain insulation and an air barrier make sense in this situation? (opening the balloon frame wall from either inside or outside seems wrong because of the solid sheathing in and out)
Any guidance would be so greatly appreciated,
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