How to Measure Moisture Content in Wood?

Measure Moisture Content in Wood

There are two main ways of measuring wood moisture content: oven-dry testing and moisture meter testing. Let’s go over the basics of each…

1. Oven Dry Testing

Oven dry testing is the oldest method for measuring the moisture content of the wood. The process is time-consuming but produces accurate results if followed correctly. Here’s how it works…

The wood sample being tested is dried in a special oven or kiln and its weight periodically checked. Once the wood sample’s weight stops changing, its weight is compared to what it was before the drying process began. This weight difference is then used to calculate the wood’s original moisture content.

While oven-dry testing, if followed correctly, offers accurate results, there are a few drawbacks:

  • It takes a long time – We’re talking about hours. The oven drying process must be done slowly or the wood could burn and the test results will be worthless.
  • It will render the wood unusable – It often happens that oven drying over dries the wood to the point where it’s unusable.
  • It requires a special oven or kiln – Most hobbyists who work with wood don’t have an oven that’s capable of producing accurate results.

These three drawbacks mean that oven-dry testing usually isn’t the option of choice for hobbyists who work with wood.

2. Moisture Meter Testing

The fastest way to test the moisture content of wood is to use a moisture meter. There are two main types of wood moisture meters, pin-type and pinless.

Pin-type Wood Moisture Meters

Pin-type meters use penetrating electrodes and measure the wood’s moisture content using electrical resistance. Since water conducts electricity and wood doesn’t, the dryness of the wood can be determined by the amount of resistance to an electrical current. Dryer wood produces more resistance than wetter wood.

Pinless Wood Moisture Meters

Pinless meters are non-penetrating and read the moisture content via a non-damaging electromagnetic sensor that scans the wood. Because pinless meters scan the wood’s surface and cover a larger area than pin-type meters, they provide a more thorough picture of the wood’s moisture content.

Pinless meters also don’t leave damaging pinholes on the wood’s surface. This makes pinless moisture meters perfect for measuring the moisture content of things like expensive hardwood floors.

How to Measure Moisture Content in Wood with a Moisture Meter?

Pin-Type Moisture Meters

The general process for using pin-type moisture meters is as follows…

  • Insert the pins into the surface of the wood you want to test.
  • Make sure they’re aligned with the grain and not across it.
  • Turn on the meter. The electrical current will then move from pin to pin and measure the resistance encountered.

Pinless Moisture Meters

Pinless moisture meters are even easier to use. Just press the scanning plate against the wood’s surface, turn on the meter, and receive the reading.