Commercial Building Inspector B2Building EnclosureMedium
An inspector is evaluating the installation of roof edge flashing on a flat roof. The building is located in an area with a basic wind speed of 115 mph (185 km/h). According to IBC Section 1504.5, how must roof edge flashing and coping be secured to resist wind uplift forces?
- ABy being weighted down with ballast material at all edges.
- BBy being mechanically fastened in accordance with the manufacturer's published installation instructions.
- CBy being adhered directly to the roof membrane with a compatible adhesive.
- DBy fasteners spaced at a maximum of 12 inches (305 mm) on center.
Show answer & explanationAnswer & explanation
Correct answer: B. By being mechanically fastened in accordance with the manufacturer's published installation instructions.
IBC Section 1504.5 requires roof edge flashing and coping to be designed and installed to resist wind loads in accordance with Chapter 16 and the manufacturer's published installation instructions. Mechanical fastening is almost always required, with specific spacing and type determined by the manufacturer based on tested performance.
Why the other options are wrong
- A. Ballast is used for some roof membrane systems, but not typically for securing roof edge flashing and coping directly.
- C. Adhesion alone is generally insufficient for resisting significant wind uplift on roof edge flashing and coping.
- D. While fasteners are used, a universal 12-inch spacing is not specified; the exact spacing depends on the product, wind zone, and manufacturer's instructions.
Roof Edge Flashing Wind Resistance
The requirement for roof edge flashing and coping to be robustly secured to withstand prescribed wind uplift forces.
- Must comply with Chapter 16 (Structural Design) for wind loads.
- Installation must follow manufacturer's instructions.
- Mechanical fastening is critical for secure attachment.
Memory trick: Wind uplift is fierce, so flashings must fiercely fasten.