Philly Flat Roof Damage Signs After Winter

Signs of Winter Flat Roof Damage to Look for This Spring in Philadelphia

Sterner Brothers Roofing • May 28, 2025

Signs of Winter Flat Roof Damage to Look for This Spring in Philadelphia

Flat roofs are popular in many Philadelphia neighborhoods, from South Philly rowhomes to Center City commercial buildings. But our brutal winters—snow, sleet, and freezing rain—can leave these roofs vulnerable. At Sterner Brothers Roofing, we specialize in flat roof inspections and repairs. Here's what Philly homeowners should look for this spring.

1. Ponding Water on the Roof Surface

One of the biggest issues with flat roofs is standing water. If your roof doesn’t drain properly after snow or ice melts, that water can seep into seams and lead to leaks or structural damage. Check for:

Pools of water that don’t drain within 48 hours
Water stains or bubbling on interior ceilings
Soft spots or sagging areas on the roof

2. Cracks or Blisters in Roofing Membrane

Freezing and thawing cycles in Philly winters can crack or blister your flat roof’s membrane. Over time, this damage compromises the waterproof barrier. Look out for:

Cracks in modified bitumen, EPDM, or TPO surfaces
Blistering or bubbling due to trapped moisture
Visible seams pulling apart

3. Interior Water Leaks or Stains

Flat roofs can conceal leaks until the damage becomes serious. As snow melts, water may infiltrate through compromised areas. Be alert for:

Brown or yellow stains on your ceiling
Moldy smells or damp insulation in the attic
Peeling paint or warped drywall

4. Blocked Roof Drains or Scuppers

Flat roofs rely heavily on proper drainage. Winter debris like leaves, ice, or broken branches can block drains and scuppers, leading to ponding and backup. Inspect for:

Gutter overflow or slow-draining roof water
Ice dam formation around roof edges
Vegetation or debris buildup near drains

5. Damaged Flashing or Roof Edging

Cold weather can cause flashing and parapet wall caps to pull away or warp. That can let water in where your roof meets walls or structures. Check for:

Rusted or detached metal flashing
Gaps or cracks around rooftop units, skylights, and edges
Loose or missing edge metal

Protect Your Philly Flat Roof with a Spring Inspection

With Philadelphia’s unpredictable spring weather, now is the time to act. A quick inspection from Sterner Brothers Roofing can catch small issues before they become big, expensive repairs. We specialize in flat roofing systems for both homes and commercial buildings across the city.