Designers of commercial and industrial buildings with low-slope roofs - such as sports arenas, schools, manufacturing facilities, office buildings and hospitals - face one of the toughest structural challenges of all: designing a roof system that withstands wear and tear and the toughest of weather conditions while remaining watertight.

About seven to ten percent of all commercial and industrial roofs today are covered by a vinyl roofing membrane. At the most basic level, vinyl roofing membranes are weatherproofing sheets that utilize flexible vinyl as a primary component, and all fall into the "single-ply" family of roofing membranes. The term single-ply distinguishes vinyl roofing membranes and similar products from the category known as built-up roofs, which are literally constructed on the roof of a low-slope building using asphalt and roofing felts. There are three main categories of single-ply roofing - modified bitumen (asphalt-based rolled roofing), thermoset (such as EPDM) and thermoplastic - and vinyl falls into the thermoplastic category.

Quite simply this means that thermoplastic materials can be formed, fused or changed using heat. This property makes vinyl roofing membranes particularly well-suited for heat-welding of seams in a variety of temperature ranges. Heat welding simply refers to the method of creating strong air- and water-tight seams using hot-air welding equipment and are fast becoming the industry standard for single-ply roof installations.

Most vinyl roofing membranes on the market today differ slightly. Nearly all are internally reinforced with a woven fabric (polyester or fiberglass) which improves the strength and stability of the membrane. Vinyl membranes are appropriate for use in any of the three main roof applications, depending on building specifications:

•Mechanically attached systems, in which the membrane is affixed to the roof deck, typically with a screw and metal plate or fastening bar. The fasteners are then covered and sealed against outside weather.

•Adhered systems, in which the membrane is "glued" to the roof deck or suitable substrate using either a solvent- or water-based adhesive.

•Ballasted systems, in which the membrane is secured to the roof system using weight, typically roofing pavers, blocks or stones.

Flexible and lightweight, vinyl roofing membranes have a proven and tested performance history that goes back more than 30 years in the global industrial and commercial roofing marketplace.