Commercial Building Inspector B2Building EnclosureEasy
An inspector is evaluating a commercial building's roof assembly that utilizes a fully adhered single-ply membrane. The building is located in an area with a design wind speed of 130 mph (209 km/h). Which of the following is the primary method used to ensure the membrane resists wind uplift forces?
- AIncreased membrane thickness
- BMechanically fastened insulation boards
- CAdhesive bond strength and perimeter fastening
- DBallast application
Show answer & explanationAnswer & explanation
Correct answer: C. Adhesive bond strength and perimeter fastening
For fully adhered single-ply membranes, the primary method of resisting wind uplift is the strength of the adhesive bond between the membrane and the substrate, often supplemented by enhanced fastening at perimeters and corners where uplift forces are highest.
Why the other options are wrong
- A. While thickness can affect durability, it's not the primary method for wind uplift resistance in fully adhered systems.
- B. Mechanically fastened insulation boards support the membrane but don't directly secure a fully adhered membrane against uplift.
- D. Ballast is used in loose-laid systems, not fully adhered systems.
Fully Adhered Single-Ply Wind Resistance
The method by which a fully adhered single-ply roofing membrane resists wind uplift forces.
- Primary resistance comes from the adhesive bond.
- Perimeter and corner zones require increased fastening.
- Adhesive type and application rate are critical.
Memory trick: Wind tries to lift the roof; the bond holds it aloof.