- Q.Is there a spray-on
waterproofing that's compatible with ICF foundations
— that won't "melt" the polystyrene?
responds: When waterproofing ICFs, we use a
spray-on polymer-modified membrane —
either Tremco's Tuff-N-Dri or GMX's Ultra-Shield.
The GMX product comes with a 20-year warranty, even
when applied to ICFs. The key thing with ICFs is to
use a water-based formulation rather than a
solvent-based one, which would destroy the
Even though these coatings have the ability to
withstand hydrostatic pressure, we always install a
vertically stranded drainage board to protect the
membrane during backfill. With ICFs, the R-value of
the drainage board is not important, so the minimum
thickness (typically 3/4 inch) can be used. As with
any foundation drainage method, a perimeter drain
tile in a bed of clean stone is also needed;
usually, the coating manufacturer's warranty
Bruce Richgels is an account representative for
Waterproofing Inc., a Minneapolis-based company
specializing in foundation waterproofing.