FM testing of coatings emphasizes which aspects, particularly for SPF roofing?

• A. Water absorption rates only.
• B. Surface roughness.
• C. Weathering and impact on coatings, especially for SPF roofing.
• D. Thermal conductivity only.

Answer: (C)

FM coating tests for roofing focus on how coatings endure environmental exposure and physical abuse over time. For SPF roofs, the foam underneath is susceptible to UV degradation, moisture ingress, and damage from weather and impacts. The coatings must withstand weathering—UV exposure, temperature cycling, humidity—and maintain adhesion and barrier performance after such aging. They also need to resist impact and abrasion from hail, foot traffic, wind-driven debris, and other mechanical stresses that can compromise the protective layer. This combination—durability under long-term weathering and resistance to physical impact—is why weathering and impact on coatings is the key emphasis for SPF roofing.

Water absorption rates, surface roughness, and thermal conductivity aren’t the primary focus of FM coating performance tests for this application, even though those factors can matter in broader contexts.