Pin-type moisture meters measure resistance from point to point, then translate that into moisture content — the lower the resistance, the higher the MC. The type of material also affects the reading; I like this Extech model MO220 because it can be calibrated for hardwood or softwood and for many different species. Added functionality — like the ability to store data and download it to a computer — can drive the price of a meter up to $500-plus. The GE Protimeter, the Lignomat, and the Delmhorst are also good meters.
I take a measurement on the plate and in two spots on the stud, one near the plate and one about chest high. It’s important to bury the pins in the stud all the way to ensure accurate readings.
I use a Sharpie to mark the MC% and date on each stud I test. If the stud is in need of drying, I’ll mark a subsequent reading that shows a drop in moisture content of 1 or 2 points. I rarely mark more than three readings. Keeping track of how fast the wood is drying helps me estimate when moisture content will be low enough that I can schedule insulation and drywall.
The two-speed Quest C1000 (right) uses 2.4/2.8 amps (low/high) to move 2,700 cfm. The Quest A3000 box fan (left) operates in the same range, but its airflow is more diffuse. Because this equipment will get abused in the truck and on the site, I look for a durable molded plastic shell. Good commercial-grade fans start at about $300, and I own mine because I use them in a variety of situations (such as drying drywall mud). But they can also be rented from many of the national and local rental companies at a cost of about $10 per day or $150 per month.
No matter what the temperature is, wood won’t dry very fast in high humidity. I check outside humidity mainly to determine if a dehumidifier will be necessary. Here my Extech Humidity/Temperature Pen is reading 78.7°F, but humidity is also high at 75.7%. If humidity stays above 60% for 24 hours, I’ll bring in a dehumidifier.
Like all of my dehumidifiers, this Quest PowerDry 4000 has a built-in hygrometer. If I’m in the drying stage I set it to “Always On.” If I’m drying joint compound or paint, I set it to 55% RH (the range is 30% to 70%). If I’m keeping a house stable from trim stage onward, I’ll set it for around 45% RH.
Home Certified of Portland, Ore., provides temporary heat with electric heaters, which are typically set up after the shell is enclosed and used until the dust level in the house is low enough to run the home’s hvac system (usually about the time carpet is installed).