MOISTUREmeters $ 15–$460+
Moisture is a stealthy force in buildings, typically as invisible as it is universal, and the fundamental tool to detect it has long been the moisture meter. Lumber, furniture, and flooring companies rely on moisture meters to guarantee their products are below a promised moisture content (typically 7% to 8% for flooring) and will not shrink or deform once in the hands of the end-user. Contractors use moisture meters to determine if rooms or concrete subfloors are dry enough to install flooring, or to assess flood damage. In building inspection, taking multiple moisture readings in a careful pattern can detect areas that exceed normal moisture levels. This may explain why paint is peeling, wood is deteriorating, or brick is spalling—and even point to causes, such as a leaky roof. Like their kindred inspection tools, moisture meters come in three common types. PIN-TYPE METERS, the original versions, work by penetrating the material surface with two pins, then measuring the electrical conductivity between the them: more moisture, more electrical flow. Conductivity is displayed as a number (once by analog meter, now usually digital). Meters are typically calibrated for wood to directly read percentage of moisture content, but they’re also applicable to other materials, such as gypsum (drywall), acoustic tile, or masonry when interpreted on a relative scale of 0 to 100. Some meters now use colored displays, such as red for high moisture content, green for dry. Since the pins must be inserted into the surface, readings can depend on the depth of penetration and, in some situations, do not qualify as a non-destructive test. However, pins make this the only meter type that can detect the exact location of moisture. PINLESS METERS (aka EMF and capacitance meters) avoid pin issues by identifying moisture via the principle of electrical capacitance. Here, the tool emits an electromagnetic field through sensors pressed against the material, then measures the material’s ability to store energy. Pinless meters are the tools of choice where any impact to the surface is out of the question—say, taking readings over decorative wallpaper. However, since they can read to ¾” to 1” below a surface, they also have the ability to evaluate moisture beneath finishes such as bathroom tile or sheet flooring that cannot be penetrated or do not show any evidence of moisture.
ALL-IN-ONE METERS (aka pin/pinless) combine both meter types in one tool, and are popular with professionals who want to compare readings— one to find a high moisture area, another to pinpoint its location. Through indirect evidence, a moisture meter can find more than moisture—problems like insects or mold.