How to Detect a Leaking Roof

Examine the ceiling of your home on a rainy day. Turn on a flashlight and shine the beam onto the ceiling. Look for reflections on the ceiling surface indicating the presence of water, then mark the wet area with chalk.

Place a ladder against the side of the house on a clear day. Climb the ladder to the roof and proceed to the general location of your leak. Have an assistant tap the marked area on the ceiling from the inside. Follow the tapping noise until you reach the leaking area.

Examine the area for loose shingles or missing or loose rubber seals around pipes, vents or flashing.

Have the assistant run a water hose up to you on the roof. Ask your helper to return to the interior of the home with the flashlight.

Turn on the flow of the hose and direct the water toward the suspect areas. Direct the hose at each suspect location for up to five minutes. Have the assistant shine the flashlight onto the ceiling interior and look for the reflection of the flashlight beam off the ceiling in the marked location. Reflection is a sign of continuing leaks.

Have the assistant mark the location where the first signs of water occur in order to mark the source of the leak, and call out the location to you on the roof. Shut off the water and note the exact location of damage for later repair. Carefully climb down from the roof, avoiding the water from the hose as it could cause loss of footing.