(Also referred to as ”edge wrinkle.”) 1) A half-cylindrical or half- conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of ply sheets during installation; 2) In shingles a half-conical opening formed at a cut edge.

SPFA believes that the path to a healthful, safe, high-quality and performing SPF installation travels through the hands of a knowledgeable, trained, experienced, and ideally PCP-certified professional contractor.