Preparing Your Flat Roof for Winter

Flat roofs are particularly vulnerable in winter. Standing water can freeze and expand, putting stress on joints and flashings. High rainfall and blocked drains can cause water to back up. A pre-winter check can prevent costly repairs.

Autumn/Winter Flat Roof Checklist

• Clear all leaves, debris, and moss from the roof surface
• Clean gutters, downpipes, and outlets thoroughly
• Check that all drains are free-flowing
• Inspect flashings around walls, upstands, and penetrations for signs of lifting or cracking
• Check the membrane for blisters, splits, or open joins
• Inspect the perimeter trim and drip edge
• Check inside the building for any signs of dampness or staining below the roof

Frost and Ice

Modern roofing membranes — EPDM, GRP, and single-ply — are designed to cope with freezing temperatures. However, existing weaknesses in the membrane will be exacerbated by freeze-thaw cycles. Cracks and splits should be repaired before winter, not left until spring.

Snow Loading

Heavy snowfall adds significant weight to a flat roof. UK building regulations require flat roofs to withstand typical snow loads, but if you notice unusual deflection or creaking in severe conditions, get a structural inspection.

After a Storm

Check the roof after any significant storm. High winds can lift flashings and perimeter trims. Debris can block outlets. Catching and fixing minor storm damage quickly prevents it becoming a major leak.