Moisture that has penetrated a roof membrane will cause thermal irregularities in a roof, so IR cameras can help diagnose roof leaks. For example, after the sun has set, areas of moisture under the roofing may show up on an IR camera as hotter spots—because the water dissipates heat slower than the surrounding, drier areas.
This information can be valuable to a solar installer and the client. If roof leaks are present prior to installation, the IR camera can document them, and the customer can be encouraged to replace the roof. This can also protect the installer from liability—if a leak becomes apparent after installation, the documentation will verify that the leak was not caused by the installer.
This image was taken 30 minutes after the sun stopped hitting the roof surface. The “warmer” (orange and yellow) colors indicate water under the surface, since water dissipates heat more slowly than the surrounding materials. With the IR camera, this leak was diagnosed as a flashing issue between two different roof pitches, and was resolved before installing a solar pool-heating system.