Spray foam roofing systems must be applied over a permanently adhered roof. Depending on the method of attaching the existing EPDM roof, spray foam roofing can be applied over the top of the roof.
EPDM roofs traditionally have three ways of attaching to a structure. The first, a fully attached roof, is one where adhesive has been use to completely adhere the roof to the structure. This type of EPDM installation will accept a spray foam roof system. The roof must be cleaned of all debris first, however.
If the EPDM roof is attached with screws and plates it is not a fully adhered roof. To install a spray foam roofing system over this type of EPDM roof a cover board must be put on top of the existing roof first, then foam can be applied.
Some EPDM roofs are only attached to the structure at the roof curbs and walls. To allow a spray foam roof to be installed, cover boards must be used similar to above. The stones which are holding the roof down must be removed prior to installing the foam. This method is often referred to as ballasted.
What is an EPDM roof?
EPDM is an extremely durable synthetic rubber roofing membrane (ethylene propylene diene terpolymer) widely used in low-slope buildings in the United States and worldwide. Its two primary ingredients, ethylene and propylene, are derived from oil and natural gas. EPDM is available in both black and white, and is sold a broad variety of widths, ranging from 7.5 feet to fifty feet, and in two thicknesses, 45 and 60 mils. EPDM can be installed either fully adhered, mechanically attached or ballasted, with the seams of the roofing system sealed with liquid adhesives or specially formulated tape.
EPDM is an extremely durable synthetic rubber roofing membrane that is used worldwide. EPDM is available in both black and white and is sold in a variety of widths and thicknesses. Its superior durability and cost-effectiveness are part of what makes EPDM one of the most popular flat roof systems installed in the U.S. today.
Reroofing with spray foam is also possible on these other commercial roofing system types.