by Trevor M. Weilbach, PE, and J. Eric Peterson, PE
Low-slope roofing systems are constantly changing and developing. Roofing manufacturers bring new products and assemblies to the market each year. These new products, as well as existing roofing systems, are applied over the most vulnerable location of a building’s envelope. In an effort to ensure each and every roofing assembly meets a minimum level of performance, Section 1503.of the International Building Code (IBC) requires, “Roof decks shall be covered with approved roofcoverings secured to the building or structure in accordance with the provisions of this chapter. Roofcoverings shall be designed and installed in accordance with this code and the approved manufacturer’s instructions such that the roofcovering shall serve to protect the building or structure.”
This approval process requires roofing systems and all their associated components be tested by an accredited third-party testing laboratory in their installed conditions to verify they meet minimum requirements. These tests and the associated code compliance reports are generated for each combination of components, attachment methods, and substrate conditions permitted for installation.
As defined by the International Code Council Evaluation Service (ICC-ES):
Evaluation reports are public documents, available free of charge on the worldwide Web, not only to building regulators and manufacturers, but also to contractors, specifiers, architects, engineers, and anyone else with an interest in the building industry. All of these people look to ICC-ES evaluation reports for evidence that products and systems are code-compliant.
Any combination of these variables that has not been tested and is not listed in a code compliance report will not have approval for use and does not comply with IBC if installed.
With regard to low-slope roofing systems, manufacturers provide instructions to contractors specifying the particular combinations of membrane assemblies, fasteners with placement patterns and spacing, adhesives with ribbon spacing, and other installation requirements (normally included in the standard installation instructions and material specification sheets) necessary to resist the design wind load uplift forces. The manufacturer’s installation instructions and material specifications, in conjunction with the information from the code compliance report, form the basis by which a contractor ensures the system being installed is acceptable for use per the code.
The application of the roofing must be consistent with how the systems were configured during testing. It is important to verify the information in the code compliance report and the manufacturer’s installation instructions are current and in agreement with each other and the system to be installed meets the requirements of both documents. If there are inconsistencies, they must be resolved before the installation proceeds.
A brief history of the ICC-ES
The International Code Council (ICC) was originally formed in 1994 by the three major code authorities located across the United States. Prior to the creation of ICC, model codes were maintained on a regional basis by Building Officials and Code Administrators International (BOCA), the International Conference of Building Officials (ICBO), and the Southern Building Code Congress International (SBCCI). The merger of these three bodies took several years to complete, and the first version of a national model building code was then published as the 1997 IBC.
Prior to and after the merger, each regional code authority had its own evaluation service for product testing. Those were known as the National Evaluation Service (NES), BOCAI Evaluation Services, ICBO Evaluation Service, and SBCCI Public Service Testing and Evaluation Services. On February 1, 2003, the four evaluation services combined to form ICC-ES, a subsidiary of ICC. At the time of the merger, the previous evaluation reports published by the founding agencies were still valid and were known as ‘legacy reports.’
Additionally, the legacy reports published by the parent companies prior to the merger remained in effect past the listed expiration date. However, these reports were only applicable where the specific codes referenced in that report were still in effect. ICC-ES is one example of an accredited third-party testing lab that reviews data provided by the manufacturer and verifies compliance with IBC.
While these reports are not always accepted by the authorities having jurisdiction (AHJs), they are widely accepted and regarded as the standard.