More About SPF

To the editor:

In the past August issue of the ASHI Reporter, there was an article titled “What is Spray polyurethane foam?” from the Spray Polyurethane Foam Alliance.

I find it rather odd this rather informative article includes no mention whatsoever regarding ultraviolet degradation. The article does address SPF roof system maintenance and mentions re-coating, but no reference is made to the fact that a primary reason for the re-coating is to protect the SPF from ultraviolet radiation. SPF roof coatings frequently consist of an aluminum-fibered coating specifically applied to help prevent ultraviolet degradation.

I doubt there’s a home inspector among us who hasn’t knowingly or otherwise observed such degradation: For example, when SPF is used in lieu of plumber’s putty to seal where HVAC and/or electric service lines enter structures. Initially, the surface of SPF, when applied, exhibits a smooth, light tan or beige skin-like surface. When unprotected from ultraviolet, the color darkens, the skin disappears and a dark orange, porous, sponge-like surface appears.

Mark S. Londner, AIA, ASHI Certified Inspector
LBI Home Inspection
Purcellville, Va.