In conventional building they do not insulate the slab, and if they do,
never the footings. The temperture difference between the ground and the
house meets at the foundation. Without the BlueBoard and plastic barrier
the heat drain causes a cold floor where moisture forms, some of the
moisture coming from the ground since concrete is porous and the rest
from the air. This makes it a breeding spot for molds.
The person asking for ideas for making a "safe" house has MCS, which
means he/she is very sensitive to molds. The amount of mold spores you
can tolerate with no ill health effects is enormous compared to a person
with MCS.
I agree it is not earth-friendly to use styrofoam, but a person with MCS
can not tolerate chemicals so the inside of the house will be
formaldehyde, plastic, etc. free. Very Earth friendly.
