A roof scupper can be clear while its exterior collector or downspout is blocked. Water then backs up at the wall opening and may enter behind stucco or other cladding. Inspect the entire drainage route.

What to check first

  • Look inside the exterior collector from a safe position.
  • Inspect the wall opening and flashing for gaps.
  • Check where the downspout discharges and whether water backs up during rain.

Separate a leak from a drainage problem

  1. Trace the water route

    Follow water from the roof surface through the inlet and toward the discharge point. Inspect normal drainage and any separate overflow provision.

  2. Check the waterproof connection

    A sound pipe does not prove the membrane-to-drain connection is sound. Look for loose components, separation, damaged flashing, or patch buildup around the inlet.

  3. Preserve the opening

    A compatible local repair must not reduce the effective outlet or cover its strainer. Persistent ponding, backup, or changes to drain location and size need building-specific professional assessment.

From the project archive

Scuppers flat roof repair - they were letting debris through to clog the leader header
Historical project photo · Flat Roof Doctor
Outside wall from flat roof with scuppers and leader headers
Historical project photo · Flat Roof Doctor
Scuppers flat roof repair - Leader Header not attached to wall causing scupper to leak
Historical project photo · Flat Roof Doctor

Product reference: Bergstrom Industries’ published knowledge catalog. Follow the latest product label and safety information. Historical project examples are educational and are not a specification for every roof.