As we enter the second decade of the 21st century the low-slope roofing market is still undergoing changes. The recent changes are minor modifications compared to the vast changes that occurred near the end of the last decade. In the time period from the 1980s through the end of the 1990s, the low-slope roofing market witnessed its greatest changes in materials and technologies since World War II.
The changes included the advancement of single plies and modified bitumens; the reduction of hot-applied systems; and the transformation of cold-applied and self-adhered membranes. These modifications were largely propagated by economics, reductions in the workforce and environmental issues. All of these issues continue to be vital concerns in the market. In fact, a recent poll concerning purchasing habits of roof consumers indicates that the environmental is now the number one factor in the selection of roof materials, while the material’s ease of application is the foremost among contractors.
New Codes and RegulationsIn the past decade there has been a concentrated effort to develop standards for environmental and sustainable materials. To this point, these standards have not been added to the International Building Code. However, some of these regulations have become codes in select local municipalities and States. For instance in California, Title 24 has been part of the State Building Code for a number of years. Several municipalities throughout the country have included Energy Star roof reflectivity ratings into their codes. Most industry experts agree that it is just a matter of time before the Leadership in Energy and Environmental Design (LEED) Green Building Rating System becomes part of the IBC code.
The most recent regulation that will have an impact on the roofing industry is ANSI/ASHRAE 189.1, “Standard for the Design of High-Performance, Green Buildings.” This is an update from ANSI/ASHRAE 90.1, which was modified in 2007. This new regulation provides minimum requirements for high- performance green buildings. The goal of the new standard is to obtain 30 percent more energy savings than the 2007 standard. The standard covers all new buildings and new systems in existing buildings except low-rise residential buildings. This regulation provides the requirements for roof insulation R-values for every region of the country.
It should be noted that these are standards and not codes. However, most codes reference ASHRAE for compliance requirements, so it is a best practice to check the local codes on all of your projects.
Recent Changes to Attachment MethodsAlthough we are not seeing the sweeping system changes that we witnessed in the past decade, there are some material changes that will have an impact on the industry. As noted, most of these changes are occurring due to environmental issues or for the reduction of labor. The biggest impact of these conditions is in material application methods. With the substantial decrease in both hot-applied and torch-applied applications, there has been an increase in adhesive applications and mechanically attached systems.
The biggest change in roof adhesives has resulted from increased VOC regulations in solvent-based adhesives. The current Volatile Organic Compound level of adhesives is 20 percent of the total material content. Solvents are primarily added to adhesives to improve their adhesion capabilities. In the older generations of adhesives, low solvent content produced a thick adhesive that was hard to apply. As more solvent was added, the adhesive became lighter and was easier to apply.
Since the late 1990s the adhesive manufacturers have been working on producing quality adhesives that meet the current VOC content regulations. These regulations have led to the increase of water-based adhesives. There has been a significant amount of improvement in the development of low-solvent-based adhesives and some U.S. manufacturers can now produce solvent-based adhesives with 0 percent VOC content. Some manufacturers are offering latex/neoprene-bonding adhesives that are produced with no solvents.
Due to the adhesive regulations and the temperature constraints of adhesive and self-adhered applications, there has been an increase in mechanically attached systems. One of the primary concerns regarding mechanically attached membranes has been there susceptibility to wind flutter, which creates substantial interior noise and contributes to membrane-fastener separation. A primary reason for the membrane’s roof flutter is due to the width of the sheets.
When mechanically attached systems were first introduced, the width of the sheets was 5 feet. This allowed for sufficient fastening attachment and limited the chance of wind flutter. Over the years, the effort to reduce labor costs led to wider sheets that were 10 to 12 feet in width. These wider sheets have contributed to the susceptibility of wind flutter.
In an effort to eliminate roof flutter in these sheets, OMG Roofing Products has developed a securement system that -in layman’s terms - heats the existing fastener plates to allow for adhesion of the membrane to the plates without membrane penetration. The system provides increased attachment points, which ultimately eliminates roof flutter.
Other Material ChangesWith the advent of impending code changes to include roof reflectivity requirements some of the modified bitumen manufacturers have begun manufacturing cap sheets with factory applied coatings. These sheets eliminate the contractor’s labor costs that would be required from the application of the coating in the field while meeting the required reflectivity ratings.
Another emerging technology is through the installation of solar panels on rooftops. Some roofing contractors have begun partnering with solar manufacturers as installers. One of the early drawbacks of these types of applications was the increased ultraviolet transmission to the roof surface at points adjacent to this installations. The enhanced UV has led to delamination of roof membranes and increase of heat transmission in the building. In an effort to eliminate these risks, some of the material manufacturers have begun offering membranes specifically designed for application with solar panels.
There are currently enhanced UV-modified bitumen sheets and 80-mil thermoplastic membranes available for these applications. Another solution is to provide an application of a reflective coating over the existing membrane in these areas.
For the steep-slope residential market, some recent changes include reflective shingles and lifetime warranties for laminated shingles.