It's hard to imagine forming a foundation with rigid foam blocks, which when filled with concrete provide a structurally sound R-20 wall. As a builder I have been intrigued with this type of product, particularly due to the high cost of conventional foundation forming where I live in Bar Harbor, Maine. Because Bar Harbor is a granite-bound island, you have few opportunities to dig a standard foundation hole, pour a footing, and start forming up walls. Foundation formwork is costly here even on easy sites. Stone Site I had a chance to try out foam forms in November 1988 when my wife and I started building our own home. The site consisted of a thin layer of "blueberry sod"
