Roofing: present and future

Store Equipment & Design, Jan, 2000 by Thomas L. Smith

The near future promises continued evolutionary changes to the revolutionary roofing developments of the 1980s

The 1980s were revolutionary in the roofing industry. Single-ply and modified bitumen membranes gained a significant presence in the marketplace, where traditional built-up roofs had once captured nearly all of the low-slope roofing work.

The 1990s saw evolutionary changes--refinements in newly introduced products, and substantial growth in the metal roofing market, for both low- and steep-slope roofs.

In the next decade, the trend will probably continue to be evolutionary rather than revolutionary, including:

* Polyisocyanurate. Polyisocyanurate roof insulation board is the predominate type used in commercial roofing, almost all of it now manufactured with an HCFC blowing agent. Though HCFC is substantially less damaging to the ozone layer than CFC, it, too, causes ozone depletion and by the year 2003 its use will be banned. At least one U.S. manufacturer has already converted to an HCFC replacement.

The transition to replacements is technically challenging, carrying the risk that some marginal or poor quality insulation boards will be produced as manufacturers learn the nuances of their new products. To minimize the risk of obtaining problem boards, roof designers and contractors should be cautious when specifying/purchasing polyisocyanurate that has been made with HCFC-substitute blowing agents.

* TPO single-ply roofs. It is unlikely that new types of roof membrane will emerge soon, but a single-ply membrane developed in the 1990s may take a larger market share: thermoplastic polyolefin (TPO). Gaining popularity recently, TPO is typically white, and is similar to the PVC membrane. Problems have been reported with early-generation TPO products, but refinements may occur, and TPO appears to be a permanent and significant addition to the single-ply family.

* Sustainable roofs. As the movement toward environmentally friendly construction accelerates, greater attention will be given to sustainable roofing. Sustainable construction, with its goal of minimizing the effects construction has on the environment, involves reducing energy consumption costs, enhancing longevity and using materials and systems that have minimal environmental impact and that can be reused or recycled.

Although much research and development of design tools is needed before sustainable roofing concepts can be fully implemented, sufficient knowledge now exists to implement energy-efficient designs and to achieve longer-lasting roofs. One small aspect of sustainable roofing is now facilitated by the U.S. EPA Energy Star program, which recognizes roofing products that are highly reflective.

Thomas L. Smith, AIA, RRC, is president of TLSmith Consulting Inc., Rockton, Ill., and a licensed architect and registered roof consultant. He is former research director for the National Roofing Contractors Association.