There are several different methods and tools that can be utilized to detect or locate water leaks or points of water intrusion. An obvious initial piece of evidence is provided by visible indicators such as water staining or mold growth on the surface of building materials. Concealed or partially concealed water intrusion issues may manifest as decaying materials, softness or deflection in ceilings, walls, or floors, or distortions in wall or floor coverings.
An infrared thermography camera is an excellent non-destructive tool for moisture detection. An infrared camera shows and captures images depicting temperature variation with a colored visual scale.
Moisture or dampness will generally be seen as a cooler area due to the process of evaporation. This will typically manifest itself as a darker blue area in the infrared image. Conversely some roof water intrusion issues can be detected using the infrared thermography camera to view the roof surface at night. Areas where moisture has migrated through the roof covering or membrane may appear as hot spots due to the moisture retaining the heat from the daytime exposure and the surrounding roofing materials cooling more quickly in the cooler night environment.
"Infrared thermography is useful as an initial scanning tool to look broadly at different areas to identify potential locations of water intrusion or exposure."
The moisture meter is a tool that identifies the percent of water content or moisture content of different building materials. This is generally determined based on the electrical resistance or conductivity provided by the material. The more moisture there is, the easier electricity will flow. There are pin and non-pin type meters. The pin type meters have two small sharp metal probes that penetrate into the material. The pin type meters are good for use on such things as wood framing and subfloors. The non-pin type is better for drywall and other finishes as they are non-destructive. Many of the moisture meters have a visual or audible indicator to alert the user that the material testing has an irregularly high moisture content based on a certain threshold value.
"The measured moisture content can be compared relative to other areas in the structure and to reference materials showing typical expected values."
Another useful tool in analysis of moisture control problems is a hygrometer. A Hygrometer or psychrometer can be used to measure the relative humidity of the indoor air environment. If the indoor air has a high relative humidity and the temperature variation between the indoor air and any interior surface is large enough, condensation will form on the surface leading to potential mold growth and moisture damage.