I just read a review of a small study that found that EPS foam insulation outperformed XPS in a below grade application after 15 years in use. Here is the link: http://www.epsmolders.org/PDF_FILES/EPS%20Below%20Grade103.pdf I am curious if any of you have come across larger studies looking at this issue. Also, the publishers of the studies make EPS and I am wondering how much bias is involved here? From reading the review it seems pretty straight forward yet I have been around enough to know that you can find a study that will show just about anything. I would love to hear from any of you in the know. Trent.