Single-ply Roof Systems: The Evolution Continues.

Following is a discussion that will cover the position of single-ply roof systems within the roofing market over the past few years. It includes changes that have occurred among the manufacturers of single-ply membranes and roofing in general, new products and techniques, taking care of the single-ply roof, and a listing of resources for single-ply roofing systems.

Market Position of Single-ply Roof Systems

Over the past five years, the overall roofing market has remained relatively stable. The National Roofing Contractors Association (NRCA), Rosemont, IL, reports in their 1995 - 1996 Annual Market Survey that the total roofing market was $18.35 billion compared to $16.7 billion in 1990. The overall market dropped to $14.3 billion in 1992 but has seen steady growth since.

Single-ply roof systems have seen their share of the overall roofing market slightly increase during the last five years. NRCA's Market Survey reported in 1990 that of the $11.6 billion commercial segment of the overall $16.7 billion market, 36.9% of new construction and 31.7% of re-roofing projects utilized single-ply roof systems. That compares to the 1995 Market Survey that reports of the $13.2 billion commercial segment of the overall market, 40.5% of the new construction and 32.7% of re-roofing projects were single-ply. While single-ply systems are not garnishing the leaps in growth experienced during the 1980s, their market presence has remained strong.

Today, several varieties of single-ply systems are on the market. Some have now been available for almost two decades. Single-ply systems are categorized into two generic types: First, thermoplastic membranes are sheets where chemical cross linking does not occur. Thermoplastic materials are seamed by either hot air or solvent welding of one sheet to the next creating a direct bond of the material. Second, thermoset membranes are those that chemically cross-link (i.e. cure). Most thermoset materials are seamed with an adhesive since the cured material cannot be chemically linked.