What is required to provide resistance against wind uplift in a loose-laid EPDM single-ply system?

• A. Ballast
• B. Adhesive
• C. Screws
• D. Sealant

Answer: (A)

Wind uplift resistance in a loose-laid EPDM single-ply system comes from ballast. The membrane isn’t bonded or fastened to the substrate, so the only reliable way to keep it in place against upward wind forces is to place weight on top of it. Ballast—such as concrete pavers or river rock—adds inertia and friction, holding the membrane down across the field and along the edges, with the weight distributed according to the uplift design requirements. Adhesive would create an adhered system, not loose-laid; screws would create penetrations used for mechanically fastened systems; sealant doesn’t provide the sustained, overall weight needed to resist wind uplift. So ballast is the required element for wind uplift resistance in this setup.