Re: Adding foam insulation to wall cavities that already contain fiberglass insulatio
The one negative that I see .....
The existing fibergalass will take up volume in the wall cavity. When the fiberglass becomes compressed by the foam it may create areas within the foam that wouldn't be a uniform thickness and possible voids.
This would also affect the advantage of the foam to seal gaps that it could if there wasn't anything in place to impede it.
When the fiberglass becomes compressed it's insulating performance is greatly reduced.... having little advantage other than taking up space in the wall cavity.
I'd be curious to see with an infrared scan if there would be hot/cold spots within the wall cavity using this method.
Just my guess.
"" an ounce of perception -- a pound of obscure "