Moisture Meter

How to Choose a Moisture Meter

Moisture meters fall into two main types: pin (invasive) and pinless (non invasive). Each has strengths. Inspectors and restoration techs often carry both because some materials and situations only one will read accurately.

Pin Moisture Meters

• Two metal pins push into the material. The meter measures electrical resistance between them.
• Best for wood and small areas.
• Leave small holes that may need to be filled in finished surfaces.
• Accurate from about 6 to 40 percent moisture content in wood.

Pinless Moisture Meters

• Capacitance sensor pressed against the surface.
• Best for finished walls, drywall, concrete and flooring where pin holes are not acceptable.
• Reads to about 3 quarters of an inch deep.
• Faster to scan large areas.

Material Specific Settings

Wood, drywall, concrete and flooring all conduct electricity differently. A good meter has presets for each common material so the percent or relative scale reads correctly. Some pro meters store hundreds of species correction factors for accurate wood readings.

When to Use Which

Use pin meters for confirming a single point reading on framing lumber and hardwood. Use pinless meters to scan large areas of finished walls and floors during a flood remediation walk through. The combination delivers a faster more reliable picture than either alone.

Pair a moisture meter with a thermal imager to find the wet pattern visually and a commercial dehumidifier to dry the area once detected.

Frequently Asked Questions

What is a normal moisture content for drywall?

Dry drywall measures below 1 percent on most pinless meters in absolute mode, or 17 percent or lower in wood equivalent scale. Anything above 1 percent (or 17 percent wood equivalent) suggests active moisture and warrants further investigation.

Can I use a wood moisture meter on concrete?

A pin moisture meter calibrated for wood will not give accurate readings on concrete. Use a meter with concrete or relative readings, or a calcium chloride moisture test for sub floor evaluation before flooring install.

How accurate are pinless moisture meters?

Quality pinless meters are accurate within 1 to 2 percent of the true value when calibrated to the material. They are slightly less precise than pin meters at any single point but cover much more area in the same time, which makes them more useful for surveying.

What does a moisture meter actually measure?

Pin meters measure electrical resistance, which decreases as moisture increases. Pinless meters measure dielectric constant, which increases as moisture increases. Both are converted to a moisture content reading using the meter's calibration tables.