Standing Water on a Flat Roof: Drainage Comes First

What to check first

• Document where water collects and how it reaches an outlet.
• Check drains and scuppers for debris without approaching unsafe edges.
• Have persistent ponding and signs of deck deflection assessed before adding another coating.

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.

Watch the field examples

These archive demonstrations show individual projects. Use the current guidance above and Bergstrom’s published instructions if an older video shows a different product or method. Torch work shown in installation videos is professional work.

From the project archive