If you’re dealing with a roof leak in Philadelphia during winter, the problem usually isn’t “new”—it’s finally showing itself. Freeze/thaw cycles, wind-driven rain, and blocked drains can turn a small weak point into active leaking fast. For many rowhomes and commercial buildings, flat roof repair becomes urgent in January because water has fewer places to go, and ice can force it under seams and flashings.

Below is a practical, contractor-style checklist we use when diagnosing emergency roofing calls in Center City, Kensington, South Philly, and Strawberry Mansion—especially on modified bitumen, EPDM, and older built-up roofs.

1) Start with drainage: scuppers, gutters, and internal drains

Most “mystery leaks” start with water that can’t exit the roof. Winter debris + ice = standing water (ponding), and ponding leads to seam stress and membrane breakdown.

• Clear leaves and roofing granules at scuppers/drains
• Check for slow-draining areas after rain
• Look for overflow stains on parapet walls (a big clue water is backing up)

2) Inspect seams, edges, and penetrations (the usual suspects)

On flat roofs, the leak is often at the transitions—not the field of the roof. Pay close attention to:

• Membrane seams (lifting, cracking, open laps)
• Perimeter edges (drip edge separation, rusted metal, missing fasteners)
• Pipe boots and vent stacks (split rubber, loose clamps)
• Skylight curbs and rooftop units (failed sealant, exposed fasteners)

3) Don’t ignore flashing and masonry tie-ins

Philadelphia buildings love parapets—and parapets love to leak when flashing fails. If the roof meets brick, stucco, or stone, water can travel behind the wall and show up far from the entry point. Signs include:

• Efflorescence (white salt stains) on interior brick
• Bubbling paint at ceiling lines near exterior walls
• Damp plaster after wind-driven storms

4) Track the leak like a pro (not like a guess)

A ceiling stain is rarely directly below the hole. Water can travel along joists, ducts, and low points. A proper inspection focuses on:

• Attic/roof deck moisture patterns (when accessible)
• Cold spots and wet insulation zones
• Matching exterior roof features to interior damage lines

5) Choose the right repair approach (patch vs. restoration vs. replacement)

A good roofing contractor in Philadelphia will recommend the least invasive fix that actually holds up:

• Targeted repair for localized seam/flashing failures
• Roof coating/restoration when the membrane is generally stable but aging
• Replacement when widespread saturation, recurring leaks, or structural issues are present

What to do right now if you have an active leak

• Catch water and protect floors/furniture
• Take photos of interior staining and exterior roof conditions (if safely visible)
• Avoid climbing onto the roof in winter conditions—slips are common and dangerous
• Schedule a diagnostic visit so the repair is based on evidence, not guesswork

Need flat roof repair or roof leak help in Philadelphia? Philly Roofing LLC handles leak tracing, emergency tarping (when needed), flashing repair, and long-term solutions for rowhomes and commercial properties across Center City, Kensington, South Philly, and Strawberry Mansion. If you’re seeing stains, bubbling paint, or repeated leaking after storms, it’s time to stop the water at the source—not just repaint the damage.

Outbound reference (safety guidance for roof work):
https://www.osha.gov/fall-protection