So one of your clients wants a refinished basement. Hardwood flooring is a great option because of its ability to bring life into any space, even one as dreary as a basement.
But given the fact that wood is hygroscopic, you might be suspicious of the idea it’s even possible to install wood floors in a basement. It’s certainly possible, but not without taking a few precautions.
Here are a few things to keep in mind when you’re planning to install a wood floor in a basement:
In a basement, engineered flooring is the safest choice
A basement is considered a below-grade environment and thus demands a floor with added dimensional stability to prevent moisture-related problems.
Engineered flooring is recommended for installation in below-grade environments because it is much more dimensionally stable than solid wood, allowing it to handle moisture changes without cupping or splitting out.
Another benefit of using engineered flooring in a basement is that exotic species are not out of the question.
Installing a hardwood floor over concrete
When you’re dealing with concrete and wood, moisture and relative humidity should be your primary concerns. You must take accurate and frequent measurements of both throughout the installation process.
To measure the moisture content in the flooring, use a pinless meter like the Wagner MMC 220 to avoid creating unsightly pinholes in the surface of the wood.
Take several moisture and relative humidity measurements of the concrete slab using a moisture meter like the Wagner Rapid RH. Watch our video on measuring moisture in a concrete slab.
Note that you cannot install a hardwood floor over freshly-poured concrete because the excess moisture in the concrete will cause problems in the wood. A concrete slab must be at least 60 days old before you can install anything over it.
However, keep in mind that moisture measurements always take precedence over age; a concrete slab that is older than 60 days might still be too wet for a hardwood floor installation.
Besides ensuring that the concrete slab is dry enough for a wood floor installation, you also have to make sure that the concrete is in good condition.
Look for cracks and blemishes in the concrete, and check for unevenness using a mason’s string, straight edge, or laser. Any high spots will have to be ground down, while low spots will have to be filled in with leveling compound. Read our guide to prepping a concrete slab for more information on this step.
Recommended subflooring for a basement
When installing wood floors in a basement, quality subflooring is a must. It should have good integrity and act as a strong, effective vapor and moisture barrier between the concrete and the wood. This will help prevent any cupping or other problems associated with the wood absorbing too much moisture from the concrete.
Here are a few of our recommended underlayment and subflooring materials for a basement:
Bostik Single Step for glue-down installations
Bostik SL-150 Self-Leveling underlayment
Bone Dry series of sealing products
Click here to view our complete selection of subfloors and subfloor prep products.
After the installation: Measure moisture regularly
The work doesn’t stop when the installation is complete. In order to prevent cupping and other problems, the humidity content and moisture levels in the floor and concrete slab must be measured on a regular basis.
Homeowners should also monitor the overall humidity levels in the household using a hygrometer. While there is no guaranteed way to control humidity levels throughout a home, monitoring can help homeowners spot any potential problems as soon as they arise.