Interpreting Moisture Meter Scales for Various Building Materials

Posted by Tom Laurenzi on Apr 6, 2015 1:23:00 PM

With several of different materials and just as many specified scales to measure them with, it’s easy to see how ensuring a proper moisture meter reading can be a bit of a challenge. Even if you’re sure you have the right scale for your designated project, there’s still a chance that you may have to make adjustments based on variable factors.

Take measuring the moisture in a wood surface, for instance. As the basic wood scale is calibrated to accommodate Douglas fir, not all construction-grade lumber is guaranteed to be properly measured using these scales. Due to differing electrical properties or even the temperature of the wood, getting a precise reading may likely require a conversion using a species correction table or a more specified meter that can convert the percentage of moisture content.

To help you make the most informed decisions, we’ve compiled a short list of tips that will guide you to making correct meter interpretations.

Don’t Assume

When you’ve completed your moisture content reading, it’s always suggested to double-check your results. In all reality, your reading is only as precise as the meter you’ve chosen. It’s also advised that you take into account the external factors that may affect your reading such as material temperature and the depth of the moisture.

Select the Appropriate Scale

As most moisture meters are well-calibrated for wood, you’ll have to take extra measures to ensure a proper reading if you’re using the meter to measure a surface other than wood. When measuring non-wood materials, we suggest the use of a reference scale or a meter specifically calibrated for the surface.

Depending on the type of wood, also, you may have to take extra steps to ensure a proper reading. Sometimes, adjustments are necessary for wood with different properties than that of a Douglas fir.

Make use of the wood species correction table to find the proper reading for your specific type of wood.

Adjust Your Readings for Temperature

A common point that’s overlooked when checking moisture content is the temperature of the actual material. Now, this doesn’t mean that it’s impossible to gain an accurate reading in hotter or colder temperatures, but it does mean that you’ll have to use a table to convert the reading into an accurate measurement.

As a rule of thumb, temperatures below 50°F or above 90°F should prompt you to also measure the temperature of the wood (or other material) to see if you’ll need to convert your reading.

Correctly Apply the Reference Scale

For surfaces like brick and concrete block, it’s imperative that you understand what the meter’s readings mean and don’t mean. The reference scale standing alone will only indicate high or low moisture content, whereas readings from different meters can’t be directly compared.

As another rule of thumb to test your reading, you can use the same meter to compare its measurement with another piece of the same material that is dry.

Take Moisture Readings Quickly

Timing is another factor that you must take into account. After a few seconds, some meters’ readings may drift downwards. For the best results, make sure that you jot down your readings within 2-3 seconds.

We hope you take these tips to heart when performing your next moisture content reading. Adjusting the meter to the right setting and making the necessary adaptations post-measurement will ensure you and your customers get the right readings to protect them from moisture-related errors and oversights.

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