Shower Leak Located Using Thermography

While investigating several water leaks throughout a townhouse complex, I came across this one which I found quite interesting so thought I would share some findings.

Image #1

The thermogram shows cooler areas that represent ceiling dampness in the downstairs kitchen area (confirmed with a moisture meter). Directly above this location is the upstairs shower. To determine whether the leak was a result of a leaky plumbing fitting behind the wall, the shower pan, or not the shower at all, we can use thermography to help find our answer.

There are several non-destructive techniques we can use, however in this case we've opted for systematically applying hot water to specific areas of the shower and monitoring for surface temperature changes downstairs. Showers can leak from many places so we must try and establish which exact area the leak is originating from so we can accurately advise on the corrective actions required. E.g. Is the leak from the PVC drain connections? tile grout? plumbing connections? cracked pan?

Hot water was applied to the shower drain to test the PVC plumbing connections for a potential leak. The radiant heat from this test can be seen on the thermogram taken from downstairs, however the ceiling dampness showed no change in temperature, so the drain was ruled out. 

Image #2

The next test involved blocking the drain and flooding the shower pan with hot water. Very quickly, the heat began to conduct through the plasterboard surface downstairs, confirming a failed waterproof membrane in the shower.

It's worth noting that during this process, there were no visible signs of water dripping from the ceiling, only changes in surface temperature detected with the thermal camera. As the power was already isolated the downlights were then popped out for visual confirmation and documentation. The inspection camera was used to confirm mould build-up in the sub-floor which suggested the leak had been active for some time.

It's always interesting to visualise the moisture path using thermography. In this case, the owners only saw a very small area of staining in the ceiling, however, the thermal image adds more to the story.