Need info on finishing a basement.

I looked into a product called Insofast to finish out basement walls.
It is 2" thick and can be glued to the walls. It also it has plastic ribs to screw the sheetrock to. Is there some other way to finish out the wall with a higher R-value? Also, is there some way to seal the rim joist? I am thinking of getting some spray foam and using it. Will the spray foam eat some blue Dow board I have cut and stuck between the joists?

Asked by Ryan O'Dell
Posted Mon, 03/08/2010 - 18:37
Edited Tue, 03/09/2010 - 07:16

Tags: Green products and materials

1.

Ryan,
If you want more than 2 inches of EPS (R-8), then either choose another product or install two layers of rigid foam to obtain the R-value you want.

Did you realize that I posted an answer to your question the last time you posed it — on this page?
http://www.greenbuildingadvisor.com/product-guide/cat/insulation

I wrote,
1. The Insofast panels should perform well. However, since these panels measure 2 inches thick, they have an R-value of only about R-8. They will not meet minimum R-value requirements in most of the country. In Climate Zones 4 and 5, the IRC requires a minimum of R-10 basement wall insulation. In Climate Zones 6, 7, and 8, the minimum code requirement for basement wall insulation is R-15. So these Insofast panels should only be used in Climate Zone 3 (the deep South) or warmer locations.

2. Tiger Foam can be safely sprayed over Dow Styrofoam (XPS).

3. You can use either open-cell spray foam or closed-cell spray foam over Dow Styrofoam (XPS).

Answered by Martin Holladay, GBA Advisor
Posted Tue, 03/09/2010 - 06:33