2×4 wall construction insulation retrofit
I am re-insulating my walls from the inside as this is the only option for me. It seems like any time i do any kind of rehabbing there is a lot on info available but never spot on for my plan.
Structure built 1968
Zone 6, Vermont
2 x 4 wall on slab
Exterior: 1/2″ sheeting (no house wrap), 1″ board and batten cedar, painted (not stained)
Here is what i have done so far
1. Air sealed with caulk and foam all wood to wood joints, foamed small cavities.
2. Air sealed electrical boxes
3. Installed Roxul r15
I want to increase the r-value and create a thermal break from the wood framing, i want to keep the finished thickness to the minimum, I plan on using JM 1″ polyiso foil faced.
1. Is this approach ok? And is this the correct rigid foam.
2. Is the r6.5 of this enough, i think I saw in my zone it should be at least R7.5.
3. I plan on caulking the perimeter of foam to the studs, ceiling and slab to air seal, will also tape seams. Does this make sense?
4. I was planning on tacking the foam to the studs with a few roofing nails with the assumption that when I screw the drywall it will be more than enough, is this the best way?
5. I think I read somewhere that the screw heads (from question #4) have a greater chance of popping thru the drywall due the the warmer wall and the expansion/contraction of the wood between Summer/Winter, seems plausible – what do you think? If so is there a way to prevent it?
Oh yea, I plan on doing this today – nothing like waiting for the last minute…
Thanks for your help in advanced! Mark
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