How to Manage Moisture for Stable, Beautiful Hardwood Floors

Edge Gold panels have long been a trusted subflooring material, helping provide a flat, solid base for a smooth, stable hardwood floor above. But like all wood products, proper moisture management is essential for quality installation.

If moisture content is too high or the moisture differential between Edge Gold and the hardwood is too great at the time of installation, problems can arise: Wet OSB will shrink as it dries, loosening around cleats and staples that attach the hardwood flooring and resulting in squeaks and pops. Additionally, wet OSB under drier hardwood flooring can cause moisture to migrate into the hardwood and result in cupped flooring. If the hardwood flooring is installed with excess moisture, it can warp or shrink and create gaps.

To help ensure a solid subfloor and stable hardwood, consider these easy-to-follow tips:

• Before installing the hardwood floors, get to know the Edge Gold panels underneath. Are panels properly installed, including the 1/8″ gap on all edges? When was it installed? When was the building closed up? Is the HVAC running? When was the floor last exposed to rain or standing water? These factors can help you determine whether the subfloor is too wet.

• Acclimate hardwood flooring to the interior environment according to the manufacturer’s instructions. Per recommendations from the National Wood Flooring Association (NWFA), don’t deliver hardwood flooring until the building is enclosed and temperature and humidity conditions match those that will be present once the building is occupied. Allow the hardwood to acclimate to the interior environment for at least five days prior to installation.

• Use a moisture meter to ensure the hardwood flooring has reached its equilibrium moisture content (the level at which it is no longer gaining or losing moisture) in accordance with manufacturer guidelines. It may be helpful to know the equilibrium moisture content of the local environment.

• Also use a moisture meter to check the Edge Gold panels’ moisture content. The NWFA considers a subfloor to be dry enough for hardwood installation in most regions when its moisture is 12 percent or less. The association recommends testing the subfloor in at least 20 locations per 1,000 square feet and averaging the results.

• Test the moisture on both the top and bottom of the Edge Gold panels and the bottoms of joists, especially over crawl spaces. An abnormally high reading in one spot can indicate a trouble zone that needs attention beyond simply allowing the entire floor time to dry out.

• Most types of hardwood flooring call for a vapor retarder between the hardwood flooring and subfloor to protect against moisture migrating up through the subfloor after the building is occupied. Note that this is not a substitute for ensuring a proper moisture balance between the hardwood and subfloor during installation.

• Once the hardwood flooring is acclimated and the Edge Gold substrate is adequately dry, the NWFA notes that the moisture difference between the two should not exceed 4 percent for solid strip flooring less than 3 inches wide and 2 percent for solid flooring 3 inches or wider. For engineered hardwood flooring, check the manufacturer’s requirements since they may vary based on hardwood species, other material components, and strip width and thickness.

Achieving a quality hardwood floor over an Edge Gold substrate is not difficult, and is largely the same as working on top of plywood. To avoid the costs and hassles of callbacks, take the time up front to allow for proper hardwood acclimation and a dry subfloor. With careful attention to moisture management at time of installation, the building occupants will enjoy a quality floor for years to come.

Tracie Higley
Tracie Higley