Does paint work instead of a poly vapour barrier?
We have a home built in central BC in the 70s This house was built without vapour barrier in the walls . latex primer and 2 coates of oil based paintwas used . Were getting pros and cons for either way . Looking for guidence when coming to explain referrng to resale. Thx for any help that could ease our minds about the situation
Thx Bill Fletcher Wms Lake
If a home doesn’t have a poly vapour barrier, several coats of paint, and specifically oil paint can make a suitable vapour barrier. You can even buy vapor barrier paint / vapor retarder primer. The bigger concern would be, does your home have an air barrier? More often than not over the last many decades the 6-mil poly is meant to be the air barrier as well, which is very different, read more here –
The difference between air barriers and vapor barriers and how to apply them
As for a way to explain it, a vapour barrier is in effect ‘water proofing’ walls, or at least making it water resistant. Oil paint on plaster walls or drywall will prevent moisture from absorbing into the wall cavities just as a poly vapour barrier would, but it won’t stop air leakage.