How to Determine the Structural Damage in a Drywall Leak

Determine the cause of the leak and repair it. If possible, enter an adjacent attic or crawl space to identify the problem. Faulty plumbing might be to blame, such as a broken pipe or clogged drain that caused an overflow. Water damage on the ceiling of a top floor room likely derives from a roofing problem, but rain can trickle down to lower level ceilings as well. If you can’t identify and repair the leak, hire a reputable contractor.

View the damaged drywall from different angles to determine the scope of the problem. Commonly, drywall warps when wet and solidifies after drying, creating low-hanging bulges that must be removed. But if the drywall remains flat, the leak likely is too small to warrant removing any drywall to inspect the interior, even if there is heavy staining.

Cut around warped portions with a keyhole saw. Create a roughly rectangular hole to make it easy to shape and install the replacement patch later.

Shine a halogen lamp into the cavity to identify the extent of the damage. Chances are the wood frame will remain sound, unless the leak has existed for a long time. In this case, you might notice the wood is spongy or flaky, indicating the wood is rotting and needs replacing.

Hire a mold remediation specialist if you see dark spots peppering the cavity. Dark, moist environments are perfect for mold, so an expert must analyze the mold growth to determine its extent. If you simply clean visible mold and seal the cavity, you might trap mold spores that will continue to thrive.

Set up a fan nearby to dry the moisture, which could take hours or days, depending on the extent of the leak. Err on the side of caution and keep the fan on until you are positive the area is dry. Trapped moisture can lead to mold growth, so the delay is worthwhile.