In previous articles, I have talked about how important it is to take hardwood moisture readings and document them. In today’s flooring world, having a moisture meter that has the capability to read various species of hardwoods and also to read the OSB Subfloor panels can be very beneficial. Some meters I have listed below; also have the capability to also read the temperature and air relative humidity of the area of installation. Also included is information on Thermo Hygrometers.
I have contacted several manufacturers of moisture meters and gathered information on moisture meters that have the capability to do both of these features. The moisture meters listed below, some are pin meters and others are pinless meters. The meters hit various price points and the higher price models have the capability to do more than just measure hardwood.
Pin meters feature two pins protruding from the end of the meter, between which an electric current travels and measures the moisture resistance in the wood. The pins can either be hammered or stuck into the flooring, and they must be placed in the direction of the grain for the best reading. The pins can be driven into the flooring at varying depths to determine the moisture content of each section of a particular board, making it easier to find the exact source of the moisture. Some meters feature pins insulated with latex or rubber to give a precise measurement in a specific location, which is ideal for gradient testing (measuring the moisture content of the wood at different depths of the board after installation) because the readings come only from the exact area between the ends of the pins. However, if the pins aren’t driven down all the way to the bottom of the board, or if the moisture meter is used incorrectly, a pin meter won’t detect any moisture that may be sitting at the bottom of the flooring.
The second type of wood moisture meter is a pinless or non-destructive meter, which rests on top of the flooring. These meters transmit low-frequency signals down into the flooring, which travel back up to register the average moisture content of the entire plank. These meters can measure up to 3/4 inches into flooring, depending on the meter. But for any flooring with thicknesses less than what the meter is designed to measure, the meter may measure the subfloor underneath and give an inaccurate reading. If you work primarily with 3/4 inch flooring, use a meter that doesn’t measure more than 3/4 inch to prevent the meter from measuring the material underneath the flooring. The pinless meters are considered more convenient because they don’t damage the boards by inserting the pins and are preferable to the pin meters for prefinished flooring.
Occasionally, a meter’s calibration can be lost, in which case it should be returned to the manufacturer for recalibration. Test your meter periodically with wood from a known moisture content. If using an insulated-pin meter, change the pins often because some of the insulation is rubbed off which can make the meter susceptible to improper readings. Pins should be changed depending on how often they are used and for which types of species. Inspectors should change pin with every inspection to ensure a high level of accuracy.
Take a minimum of 20 readings per 1000 sq. ft of the subfloor. Check areas that are most prone to moisture such as exterior walls, windows, fireplaces, at exterior doorways, where plumbing comes up through the floor and areas of discoloration and the center of the room as it usually takes the long to dry. For the hardwood flooring, test at least 10 boards per every 1,000 square feet from different locations in the acclimated stack of hardwood (top/middle/bottom) to make sure the moisture content of the flooring is consistent.
Lastly, record and date both the subfloor and hardwood moisture readings should any moisture issues happen after the installation.
Failure to test for proper moisture content of the wood flooring and subfloor can result in cupping and/ or other problems related to or associated with moisture and are not covered under the manufacturer’s warranty.
The meters listed below from Lignomat and Wagner has settings for many species of hardwoods, including Bamboo (Vertical/Horizontal/Strand Woven) and also has settings for reading Oriented Strand Board and Plywood Subfloor Panels.
Ligno scanner SDM
The Ligno Scanner SDM is a non-destructive (pinless) meter capable of measuring a 1/4″ deep to 3/4″. The SDM also has 71 wood group settings including Vertical/Horizontal/Strand Woven Bamboo, and also able to read OSB, Plywood, and AdvanTech subfloor panels. The 1/4″ depth works great on stacked veneers, engineered floors and whenever the surface moisture has to be measured. http:// www.lignomatusa.com/MoistureMeter/scannersdm.htm
Ligno Versa Tec
The Ligno Versa Tec is a non-destructive (pinless) meter capable of measuring a 1/4″ to 3/4″ deep and has 71 wood group settings including Vertical/Horizontal/Strand Woven Bamboo, as well as OSB, Plywood, and AdvanTech subfloor panels. The Versa Tec can also be used for checking air temperature and air relative humidity and also has an attachment for use as a pin meter. It may also be used for checking concrete Relative Humidity (ASTM F2170). The Ligno-VersaTec moisture meter is loaded with features to make your job easier: pin mode, scan mode with selectable measuring depths, special calibrations for concrete and sheetrock plus RH mode. http://www.lignomatusa.com/ MoistureMeter/moisture.meter_VersaTec.htm
The Lignomat Mini DX and DXC are pin meters that have the capability of reading over 41 species of hardwood including domestic and tropical wood species including Vertical/Horizontal/Strand Woven Bamboo as well as OSB, Plywood, and AdvanTech subfloor panels.
DXC – http://www.lignomatusa.com/MoistureMeter/moisture_pin_meters_mini.DXC.htm
Lignomat Mini DX
Lignomat Mini DXC
The Wagner MMC220 is a non-destructive (pinless) meter capable of measuring to 3/4″ deep and has 71 wood group settings including Vertical/Horizontal/Strand Woven Bamboo, as well as OSB, Plywood subfloor panels. Wagner Meters’ IntelliSenseTM Technology ensures that the MMC220 is measuring deeply IN the wood for a true moisture picture without damage to the wood surface and without interference from surface moisture. Two-button controls make one-handed operation simple. And like all of the meters at Wagner Meters, there is no need to adjust moisture content readings for temperature. http://www.wagnermeters.com/shop/wood-moisture-meters/mmc220-extended-range- moisture-meter/
The Lignomat PN and TH are Thermo Hygrometers used to measure the air temperature and humidity. The PN is shaped like a pen and can read temperature from 14°F to 122°F and Air Relative Humidity from 5% to 95%. The TH can read temperature from 14°F to 122°F and Air Relative Humidity from 20% to 90%. http://www.lignomatusa.com/MoistureMeter/moisture_meter.thermo-hygrometer.air.htm
The Wagner TH-200 pen-style Thermo-Hygrometer is an ideal and convenient tool for flooring installers, and inspectors when critical temperature, relative humidity dew point temperature information must be known. The pen-style design makes for easy carrying, and the 3-button controls are very simple to use. http://www.wagnermeters.com/shop/wood-moisture-meters/th-200-thermo- hygrometer-ww/