A.Gary Pugh, of Alternative
Building Concepts, a Santa Rosa, Calif., green
building company that specializes in SIPs
construction, responds: EPS — a
closed-cell, foamed plastic insulation with a
30-year track record — is inert to a wide
range of chemicals, will not rot, has no food
value, and will not attract insects, parasites, or
any animal or plant life.
It's also nonhygroscopic, which means it does
not readily absorb moisture, and its compressive
strength and thermal properties are minimally
affected by the small amounts (typically less than
0.2 percent by weight) of moisture it can absorb,
and by temperature cycling.
EPS insulation is manufactured to meet the
standards of ASTM C578, with ongoing compliance
with this standard addressed through a third-party
In addition, the adhesives used to laminate wood
facers to EPS insulation have to meet minimum
performance standards established by the major
codes with regard to exposure to moisture,
temperature, aging, oxidation, mold growth, and
compatibility with the EPS insulation core.
Reputable manufacturers of SIPs use adhesives
that are in compliance with ICC Evaluation Service
acceptance criteria AC05.
If a SIPs house can be picked up whole by a
tornado, dropped a few feet away, then get lifted
up by a pair of cranes and set down on a new
foundation with little or no damage to the
structure — which I've seen documented
— I'm pretty confident that these panels