Several flat roof areas can cause faults such as, roof contact with attics, drains, etc. Leakage problems may also occur in weak thinned areas due to improper installation, neglected maintenance or surface degradation due to insufficient protection of the surface layers against weathering. Very often, the flat roof is exposed to excessive wind loads, which causes dynamic shocks, constant oscillating motions and lifting of unpaved parts. Eventually prolonged wind exposure can thin the roof and cause leaks. Water that builds up on damaged areas of the roof then has an amplified negative effect on the durability of the roof. If water flows through the gaps between the insulation panels, under the non-absorbent thermally insulating layer and up to the waterproofing system, it will have a very low temperature. This will reduce the quality of the waterproofing system, which can result in condensation of water vapour inside the roof deck beneath the waterproofing system. In extreme cases, the leaking water may also overload the supporting structure of the roof deck.
However, there is a fast, relatively reliable and simple method to solve the aforementioned problem of checking flat roofs. The method is the use of a thermal camera which, due to the temperature difference of the dry spot and the penetrating humidity site, reveals the entire range where insulation is affected. Depending on the structure of the roof, it is also possible to clearly see how large the affected area and the extent of the damage alongside the fault point.
The physics behind thermographic checking of roof humidity is that the moisture-free (dry) part of the roof cools and heats up slower than the wet part of the roofs insulation. A thermographic check using a thermal camera (after the sun sets as the sun will heat up entire roof) reveals damaged areas simply by finding dry places as they are cooled faster than damp areas, which have a higher heat capacity.
Thermographic measurements should, of course, be done under the right conditions to obtain the appropriate thermograms. The most basic, but essential, requirement is a sufficient difference between daytime and sunset temperatures.