Wind Damage

Wind damage occurs when wind pressure lifts or tears roofing materials. As wind flows over a building it creates suction on the roof, strongest at corners, eaves, rakes, ridges and hips. If the uplift force exceeds the resistance of fasteners, adhesive or interlocks, roofing units lift, crease, break or blow away. Damage often starts at an edge and then progresses as the wind gets under the next course.

Asphalt shingles

On self-sealing asphalt shingles, technical literature describes a progression: uplift breaks or stretches the sealant bond, the tab flips upward, a crease forms across the shingle (usually just below the butt of the course above), and repeated flexing tears the tab off. Creases may be faint on new, flexible shingles and need close inspection with gentle hand pressure.

An important point in claims and investigations is that unsealed shingles are not automatically wind damaged. Shingles can fail to bond, or lose their bond, through manufacturing variation, cold-weather installation, dirt in the sealant, stuck release tape, thermal cycling, racked installation, under-driven or misplaced nails and age. Research cited by roof consultants found shingles tend to stay sealed for their first few years, with unsealing becoming more common later. Patterns help: wind damage concentrates on exposed slopes and edges facing the storm, while thermal or installation-related unsealing often follows diagonal or repeating patterns unrelated to exposure.

Other materials

• Tiles and slates may lift, crack or slide, especially at ridges, hips and verges, or where mortar bedding has weakened.
• Metal panels can peel back from edges if fastening or clips are inadequate; trims and ridge caps are frequent failure points.
• Low-slope membranes may billow, peel at the perimeter or tear from fasteners; loose ballast can scour the membrane.

After a storm

Owners should first look from the ground for missing pieces, debris and displaced flashings, then arrange a professional inspection. Temporary tarping limits interior damage. Higher-wind-rated products, stronger edge details and correct nailing are the main ways to improve resistance on reroofing; in some regions, fortified roofing programmes specify enhanced details.