To maintain compliance of a roof edge system after installation, which changes are generally prohibited?

• A. Fastener spacing, edge profile, or substrate
• B. Coating color
• C. Insulation nominal thickness
• D. Roof tile texture

Answer: (C)

Roof edge systems must sit at a precise height and interface correctly with the membrane, flashings, and fasteners to maintain water control and wind resistance. After installation, changes that alter these relationships can break the assembly’s performance and its compliance with the tested design.

Changing insulation nominal thickness directly affects the finished height of the roof and where the edge components terminate. If the insulation thickness is altered, the edge metal, drip edge, sealants, and flashings may no longer seal properly or align with the membrane, creating gaps, drainage issues, or potential water intrusion. It can also affect the thermal and wind performance of the edge detail, which is why such a change is generally prohibited.

Cosmetic adjustments like coating color or roof tile texture don’t impact the edge’s performance. Changes to fastener spacing, edge profile, or substrate would disrupt wind uplift resistance or sealing and typically require approved revisions or re-engineering rather than endorsement as a simple post-installation modification.