How to Control Moisture During & After Framing

Weyerhaeuser Edge™ and Edge Gold™ subfloor panels are engineered for strength and stability. But like any wood product, engineered panels are susceptible to moisture. Buckling between floorboards, warping or bowing of panels, drywall cracks and even pops and squeaks as you walk are often caused by moisture. Specifically, by the contraction and expansion that occurs as wood moisture reaches equilibrium with its environment.


Subfloor panels should be dry, both when you install them, and in their installed position. Use a moisture meter to check the moisture content of the subfloor, before any finished flooring is installed overtop the subfloor it shouldn’t be more than 4% over the expected in-use average of the finished flooring (check with your local officials for exact measurements, but that’s roughly 8-12% in coastal regions, 6-10% in inland regions, and 5-9% in drier climates).


So, how do you know if there is a moisture imbalance? Well, one of the most common complaints I hear is the presence of mold. Found nearly everywhere, mold spreads as airborne spores that begin to thrive when they find appropriate growing conditions. What’s important to remember though is that in order for mold to grow, it must have oxygen, nutrients which include many building materials, moderate temperatures, and most importantly greater than 20% moisture content.


Fortunately, if you find yourself in this situation, most building moisture problems can be prevented or corrected. Follow these best practices to reduce moisture:
[li]Properly store and handle wood products throughout the building process.[/li]

[li]Schedule deliveries to make sure panels aren’t exposed to weather[/li]
[li]Cover with a tarp during inclement weather, remembering to properly ventilate the sides so as not to trap in moisture.[/li]

[li]Use exterior moisture management systems, such as flashing.[/li]
[li]Ensure moisture control devices such as vapor barriers, ground cover and ventilation openings are installed for the crawl space.[/li]
[li]Keep up on maintenance and operation of the building, including control of interior humidity levels.[/li]
[li]If installing during warm months, ensure the building is well ventilated; during winter months, heating should be maintained near occupancy levels.[/li]

If you discover mold, there are a number of best practices to help reduce moisture in the floor framing process. For those strategies, download The National Wood Flooring Association’s “Water and Wood: How Moisture Affects Wood Flooring.”

George Hendry
George Hendry
George Hendry has spent more than 27 years in the forest products and building materials industry, 11 of them with Weyerhaeuser’s Trus Joist, Distribution and OSB Manufacturing divisions. In his current role as Market Development Manager, George applies in-depth knowledge of OSB manufacturing, installation practices, and market trends; leads a team of OSB Market Development Representatives; conducts training throughout the channel; and lends his extensive expertise to new product development and implementation.