I have a house built in the early 70’s and starting the renovations. After removing the drywall in the front foyer to replace the door and fix other problems, I found the following: Walls are 2×4, T-11 exterior sheet covered with cedar lap siding (no wrap or builders felt betwen), interior walls un-mudded draywall covered with paneling, walls to have spray foam insulation, about 1-2″. I plan to remove the old cedar siding in the process of replacing all the casement windows. Questions:
1. How long does this old spray foam insulation off-gas formaldehyde?
2. Can I cover the existing old spray foam insulation with a new layer of closed cell foam to seal off any further residual off-gas?
– My new planned wall profile is: Properly installed dry wall, layer of new “green” closed cell foam to cover the existing foam (which is very solid and stable), leave the T-11, wrap in TYVEK, install furring strips, add CORAVENT at bottom and top, and cover with LP Smartside lap siding.
1. Is this a viable plan? ( I live in middle Michigan area).
Tim
Replies
How long does this old spray foam insulation off-gas formaldehyde?>>>>>>>>>>>>.
If you are referring to the foam from the 70's, no worry it has finished off gasing a long time ago.
2 Why don't you just remove it? If it is from the 70's it will turn to powder in your hands. Bring out the shop vac. and clean it up. Then start over.
It sounds viable, but why are you removeing existing cedar claps for fake cedar LP product?? If you are set on closed cell insulation you have no need for the tyvek.