How Do Moisture Meters Work?

Moisture meters are vital to measuring moisture content and potentially preventing water damage.

There’s an easy way to catch moisture problems before they cause expensive damage to a home or commercial facility — moisture meters. Industrial cleaning and restoration professionals may have a moisture meter or two lying around, but how many know the science behind how they work? As the name implies, moisture meters measure moisture content (%MC), and they can detect problems before water damage is visible to the eye. Here’s how moisture meters work, and why they should be part of every cleaning or restoration toolkit.

Pin-Type Moisture Meters
In order to get an accurate moisture reading on any building material — whether it’s wood, drywall, or even concrete or tile — the meter has to be able to detect water content inside the material. Pin-type moisture meters use a series of contact pins to get a moisture reading.

Pin-type meters work by measuring the electric conductivity between the pins. An electrical current is sent from one pin, though the material and into a second pin. The less resistance there is, the more likely there is water in the material. The meter calculates the amount of resistance and provides a %MC for that material.

There are two ways to use pin-type meters — either penetrating the surface with the sharp pin tips or, to protect the material, by pressing the pins against the material without letting them dig into the surface. These readings may be more or less accurate depending on how the meter has been calibrated. By default, most meters are calibrated for wood, but the reading can be adjusted to suit different materials. Check the meter’s instruction booklet to find out how to correctly calculate the %MC for the material being tested.

Nondestructive, or Pinless Moisture Meters
The second type is a pinless, or nondestructive, moisture meter. These meters use an electromagnetic frequency to detect moisture, which means they don’t need to penetrate the material to be effective. This is especially useful for materials like gypsum or concrete, where it would be difficult to insert a pin-type meter.

Pinless moisture meters can read up to one inch into a subsurface, which makes it a good option for basement work, under flooring, and in bathtub and shower enclosures. The pinless option will be less accurate than a pin-type moisture meter, but it can identify any areas that need to be investigated further.

There are also combination moisture meters that offer the best of both worlds. Whichever type of meter is used, make sure it is calibrated regularly and adjustments are made for the type of material being measured.

Moisture problems are more than inconvenient. They can cause thousands of dollars in damage and may cause dangerous mold formations before they even rise to the surface. Atex has a variety of moisture meters to help cleaning and restoration professionals get to the bottom of suspected moisture problems. Shop our catalog online or give us a call at 713.944.0319 to get a quote.