Bob, I cannot fit an eps rigid board into the portal to the crawl space, as it is only 16 x 30". So I was thinking of using rockwool to put in the horizontal perimeter of the house. It has a concrete border with a 2 x 12 board on top of it, and the floor on top of that. I think I can put the rockwool on the two sides in between the 16" joists?, but on the other two sides there are no board boundaries. However, I don't know how to attach the rockwool to this horizontal beam. It is a log home and the concrete has insulation inside it, but the 2 x 12 is without any kind of insulation. Help!