CHICAGO — Much of the most serious water damage in buildings is hidden behind walls, under floors, and above ceilings — invisible to the naked eye but capable of causing mold growth, structural deterioration, and indoor air quality problems if not detected and addressed promptly.
Pin-type moisture meters measure the electrical resistance between two metal probes inserted into a material. Because water conducts electricity, materials with higher moisture content have lower electrical resistance. Pin meters are accurate and inexpensive but require direct contact with the material and leave small holes.
Impedance-type (non-invasive) moisture meters measure the electromagnetic field created by moisture in a material without penetrating the surface. They are useful for scanning large areas quickly and for assessing moisture in materials where pin holes are not acceptable, but they are less accurate than pin meters and can be affected by metallic materials behind the surface.
Thermal imaging cameras detect temperature differentials on surfaces. Wet materials cool faster through evaporation than dry materials, creating a visible temperature contrast that reveals hidden moisture. Thermal imaging is particularly effective for detecting moisture in walls and ceilings and for mapping the extent of water intrusion.
Borescope cameras — small cameras on flexible cables that can be inserted through small holes — allow direct visual inspection of wall cavities, crawl spaces, and other inaccessible areas. They are particularly useful for confirming the presence of mold or structural damage that is suggested by moisture meter readings or thermal imaging.
