Which device is used to identify moisture in building materials behind walls?

• A. Thermometer
• B. Hygrometer
• C. Infrared camera
• D. Moisture meter

Answer: (D)

Identifying moisture inside wall materials is about measuring how much water the material itself contains. A moisture meter does exactly that by testing the material’s moisture content. Pin-type meters insert probes into the wall and read electrical resistance changes caused by moisture, giving a direct, numerical moisture content. Pinless meters scan the material and estimate moisture without puncturing it. This direct reading tells you whether the wall material is within acceptable moisture levels or if it needs remediation.

Other tools serve different roles: a hygrometer measures ambient air humidity, which doesn't tell you how wet the wall material is; a thermometer measures temperature, not moisture; and an infrared camera highlights temperature differences to flag potential moisture behind walls, but it doesn’t quantify the moisture content itself.