A thermal camera shows temperature differences. Wet areas of a roof or ceiling often hold heat differently than dry areas, so they can show up as patterns on the screen.
Every roof soaks up heat from the sun during the day and gives it off after dark. Dry shingles and decking cool down fast. Wet insulation and wet decking hold that heat much longer. A thermal camera reads those temperature differences and turns them into a color picture, so the wet spots stand out from the dry roof around them — before the leak shows up as a stain on your ceiling.
What it helps us find: leaks hiding under shingles or tile, wet insulation on flat and commercial roofs, leaks around flashing, vents, chimneys and skylights, and storm damage that is letting water in.



Example thermal images. Cooler blue areas can point to trapped moisture; we always confirm by hand.
It does not see water directly through every roof material, and results depend on weather and time of day. That is why we always confirm with a hands-on check.
Related: Roof leak detection · Drone inspections · all guides
Written by Mike Davis, owner of RezComm Professional Services.
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