Roofing

Section Contents:

Relevant Standards
Code information

Relevant standards. ASTM D4434: Specification for Polyvinyl Chloride Sheet Roofing is the only nationally recognized standard created specifically for and applicable to all vinyl-based roofing membrane. For this standard, ASTM set a minimum 5,000-hour criterion for weathering performance. This is based on an accelerated weathering test that subjects the material to cycles of exposure to a xenon arc light source to simulate sunlight, water spray and elevated temperatures. All of these factors can degrade roofing membranes.

The minimum requirement for a vinyl sheet under this test criterion is that it can't show any evidence of cracking or crazing and only negligible evidence of discoloration after 5,000 hours of exposure. Vinyl roofing membranes are also subject to evaluation for fire safety by Underwriters Laboratories (UL) or another nationally recognized laboratory. Specifiers should seek vinyl roofing membranes which bear the label for a UL Class A (or comparable) fire rating.

Specific manufacturers (listed under Resources) should be consulted for more information about their products' adherence to these and other performance standards. For a complete list of all applicable standards, see the bibliography.

Code information. In general, vinyl roofing membranes far exceed the minimum requirements of model and local building codes for many performance criteria, including fire propagation and energy efficiency. Proper design of vinyl roofing systems can also enable these systems to meet even the most demanding code requirements for performance criteria such as wind resistance.