Is closed cell foam insulation worth the cost for a 75 year old home with 2×4 exterior walls?
I am remodeling my 75 year old home. I am gutting the interior walls and adding a full dormer. The exterior walls are 2×4. Is it worth the cost for closed cell foam insulation or is a traditional fiberglass insulation sufficient? Thanks, Paul
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Yes.
Also seal up the rest of the envelope via blower door testing. Also beware of moisture levels and sources next along with looking into ventilation and sealed combustion water and space heating units.
If you want to just use batts, air seal your entire exposed frame.... reducing air leaks will be worth your time and has little material cost!
Most homes that age have plank sheathing, some have some sort of asphalted felt or a heavy rosin-paper on the exterior of the planking as a weather resistant barrier, and the types of siding are myriad.
To know which cavity-fill options make sense cavity and which are potentially problematic we need to know the entire material stackup, and the US DOE climate zone. A brick veneer wall in zone 7 won't the same set of conditions and restrictions as stucco clad house in zone 2, or a clapboard sided house in Zone 5.
https://www.greenbuildingadvisor.com/blogs/dept/building-science/all-about-climate-zones