A thumbnail purview of
seven moisture meters
by Michael Fallarino
In my previous column I covered some of the rudiments of moisture meters including the types of meters, what they are capable of doing, and why I think that they are important. In this column I will focus on meters from three American manufacturers: Delmhorst, Extech, and Wagner.
Over the course of the past decade or so, moisture meters, like just about every other tech device, have become increasingly sophisticated. The world is slowly going wireless for a variety of reasons and moisture meter technology has migrated in that direction. Older meters relied primarily on information from penetrating pins to read material. While pin-style meters have the advantages of being highly accurate, spot-specific, able to reach deep into a building materials assembly, and quite definitive, they have the disadvantage of being slightly destructive.
That is, the pins (which vary in size) leave miniscule to tiny holes in the materials you have inserted them into. This should really not be much of an issue, since in most cases the tested materials will be worked on in some fashion or even replaced. In cases where the tested piece is left in place, it usually will receive a new finish.
In the case of wireless meters, the meters read a very small patch of material through a sensing plate. For the Wagner meters pictured on the opposite page, the sensing area is approximately four and a half square inches, and the Extech pinless sensor plate is just over two square inches.
It would be possible to devote a lot of space to a discussion about the advantages of pin versus pinless meters, including the machining, spacing, and depth of the pins, and the sizes of the sensor plates. The bottom line is that nearly all designs have advantages and a very strong case could made as to why it would be advantageous to have both a pin-style and a pinless meter.
Having the opportunity to polish my geek antennae by running the seven meters in this article though some rudimentary paces was a fun exercise. Interestingly, each manufacturer's meters were in close agreement with each other. That is, meter readings tended to be extremely congruent within a brand, typically displaying a difference of a tiny fraction of one percent.
I have hypothesized that the congruency within brands – but slightly larger differences across brands – reflects the relationships that the manufacturers use to synchronize the logarithmic nature of measuring moisture with the proprietary electronics of their meters. In my comparison tests, the Wagner meters tended to read two to three percent higher than the Delmhorst and Extech in tests on both dry wood and moisture-laden wood. The Delmhorst and Extech tended to be in basic agreement with each other in rudimentary tests on both dry and moisturized wood, with the Extech meters typically reading a fraction of a percent higher.
All the meters are battery operated, have an auto-off feature, come with in---structions and information on calibrating the readings of the meter across wood species where necessary, and are typically warranteed for one year. Wagner meters read moisture levels up to 30% while the Delmhorst and Extech reach into the 40% range.
It is important to note that Delmhorst and Wagner are exclusively moisture meter manufacturers. Extech, by comparison, is a manufacturer of scientific meters, as well as thermal cameras and portable printers. They manufacture a vast range of instruments in 15 different categories (such as sound meters where they offer about 20 models). In my opinion, the Delmhorst meters had the most robust build quality and the most expanded range of capacities. Extech's strengths are their contemporary and ergonomic styling coupled with their value-oriented price point.
This two-part series on moisture meters has been a mere thumbnail view of why I believe they are extremely valuable tools in assessing facets of contemporary building construction. Moisture meters can be invaluable to all sorts of contractors, including carpenters, painters, concrete contractors, flooring installers, woodworkers, building inspectors, building material forensic experts, and GCs. A few pages cannot do justice to the capacities of the meters covered considering the wide range of materials they can test, the differences between them, or the extensive lines of moisture meters that these three manufacturers produce. Interested readers should visit the websites of these manufacturers to learn more.
I would like to thank Josh Rothman of Delmhorst, Andre Rebelo of Extech, and Ed Wagner for their assistance. To learn more about the products in this article, please visit these websites: www.delmhorst.com, www.extech.com, and www.wagnermeters.com.
Mike Fallarino is a contractor in the Albany, New York, area. He can be contacted at firstname.lastname@example.org.
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