Spraying Foam Insulation on Foundation Exterior
I am wondering about the wisdom of applying spray foam insulation on the exterior of a field stone foundation. I am concerned that insulating from the inside would lead to frost damage of the lime mortar. The exterior foam would have the added benefit of air sealing where it meets the aluminum siding. A UV protective coating would would be applied over the foam. Has anyone any experience with this approach? Any concerns?
I was reading recently in FH about the possiblity of carpenter ants tunneling through, or building colonies within the foam. Should I be worried??
Replies
if the main benefit you see doing this is sealing the sill plate, why not seal the sill from the interior? you can buy a few cans and save yourself thousands.
I i have never seen closed cell sprayed in the way your refering so i can not speak to this method. i would be concerned the foam would not hold up well outside.
Field Stone Foundation
The space between the joists at the top of the foundation, beside the sill, is full of field stone as well. So the sill is 18" away. The other issue though is there are places where the wind gets behind/under the siding and blows out the electrical boxes and such. So an advantage to seal up below the siding.
I have done a lot of Internet searches and found little on this approach either. I am told that the exterior coating works well and I am considering putting a coat of paint over top to extend the life.