EXPLORING THE OPTIONS: SINGLE PLY ROOFING.

Today, single ply is an accepted alternative to built-up roofing (BUR) and is no longer marketed primarily as a reroofing product to be used over intact BUR. It may be installed loose laid and ballasted, or it may be fully adhered, partly adhered, or mechanically fastened. The single ply system does not vary a great deal from the Bur system in that they both use a structural deck, vapor retarder, and insulation, or a form topped by a poured-in-place insulating fill as a substrate. The difference is in the single ply membrane: a single sheet of rubber, plastic, or modified bitumen taking the place of three or four plies of tar- or asphalt-saturated felt laminated with asphalt or coal tar pitch. This article discusses single-ply roofing materials, applications, installation procedures, and other aspects of the subject.