Renovating an older home
We are renovating our house in North Vancouver, BC.
This area gets about 2500 mm of rain per year.
All the siding is removed and underneath, are 1×8 ship lap boards over 2×4 framing.
I removed the old building paper and covered with Typar for the winter.
I was thinking of installing inch and a half Roxul Comfortboard over top the Typar and under the rain screen but I understand that the bottom edge of the air barrier should not be sealed so that any water that gets behind it, can drain.
However, with the board sheathing, I don’t get much in the way of air sealing.
Should I remove the Typar and apply a layer of plywood over the board sheathing? I would tape all the edges of the ply. (Most likely 3/8″ spruce)
And should I overlap the top of the concrete foundation with the plywood and seal the new sheathing to the concrete with caulking?
What type of caulking is acceptable, silicone, polyurethane?
I would reapply Typar over the new sheathing.
We are also adding a short extension onto the home.
I would add 3/4 inch sheathing to match the existing 1×8 sheathing. The question is would it be ok to continue with the 3/8″ ply overtop the 3/4 inch ply so the exterior is on the same plane?
I need to fur out the original 2×4 framing to match the new 2×6 framing so I can’t make any adjustment on the interior.
All suggestions are welcomed.
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