[TheForge] Underground house

[wmullett at bright.net]

The problem with these systems is that they use expanded foam insulation not extruded foam insulation.  Expanded foam - bead board - is not a good insulation where it can be exposed to moisture because it it an open cell.  The open cell is replaced by water and the insulation looses its R value.  

Even in above ground situations, water vapor can be trapped in this insulation and reduce its value.  When used above ground, you still need to pay attention to vapor barriers and where you place them.

NEVER - NEVER use EPS insulation in a ground exposed situation.  Your just pouring your money down a hole.

Walt