Should we install cork flooring in our moisture-prone basement?
We recently had some very bad flooding in our garden-level basement after 10 inches of rain. We're going to have to remove our carpet and are considering replacing it with cork. Although this degree of rain and flooding was unusual, we live in an old house that has occasional seepage around the baseboard. What would this do to the cork? I've heard that cork is waterproof and would not be affected, but I've also heard it would peel and split and would separate from the floor.
Before you install new flooring, I would address the basement moisture issue.
- Water seepage and moisture are not only hard on floor coverings, they promote the growth of mold and mildew, which can cause poor indoor air quality.
- Cork may or may not be an appropriate floor covering for your basement—it depends on how much moisture/water intrusion you have, the type of cork flooring, and the manufacturer of the product.
Controlling moisture: French drains, sump pumps, and subfloor systems
There are a variety of methods for addressing below-grade water seepage. French drains and/or sump pumps, although expensive, can fix the problem.
French drains. A French drain is a system that moves water away from your foundation and basement to an appropriate drainage location. If installed under the basement floor, a French drain can direct water to a sump pump that forces water up from the basement area to an appropriate outlet (i.e., storm drain or drainage pit). French drains require extensive excavation, and the installation costs will vary based on the amount of labor involved (excavating through a concrete walkway, for example, can be labor intensive). French drains can also become clogged over time, especially if you have trees that lose leaves.
Sump pumps are another method of keeping the basement dry if you cannot direct water away from the foundation. They do need a backup system to keep them functioning in case you lose electricity.
As I believe we will continue to experience erratic weather patterns, one of these systems may be a wise investment; the options must be evaluated based on your specific situation.
In addition to these methods, there are subfloor systems designed specifically for basements.
- For instance, DRIcore offers a raised subfloor with a moisture barrier that allows the concrete to breathe.
- This is a simpler, more cost-effective solution if it will work for your home.
Choosing the right flooring material for your basement
When considering cork flooring, you need to check with the manufacturer of the product to assure they recommend below-grade/basement installations. Many do not.
Glue-down tiles would not be a wise choice as they can delaminate if glued directly to a moist surface. Natural Cork recommends their tongue-and-groove floating floors for basements, installed over a 6-mil film of polyethylene as a moisture barrier. (Refer to the manufacturer's installation specifications for detailed instructions.) The floating floor is not attached to the subfloor and rests on top of the moisture barrier.
You should be aware that these floating floors (from any manufacturer) have a fiberboard core that is not waterproof. If water were to come in direct contact with the flooring, it could cause permanent damage.
If you can control the direct moisture exposure to the cork, I think it is an excellent choice for a basement. It is naturally mold and mildew resistant, soft to walk on, and it provides a thermal barrier against the cold concrete. Basically, cork floors feel good underfoot. Also, they are manufactured from a rapidly renewable source—the bark of the cork-oak tree. When choosing cork flooring, be sure to search out companies that use low-VOC binders and sealers.
If you cannot control the water intrusion in your basement, I would recommend you install ceramic or porcelain tile with a high recycled content.
For more information:
Read Mary Cordaro's Q&A "I just finished my basement. Can you help me choose mold-resistant flooring?"
Read GreenHomeGuide's Ask A Pro article "Is cork a good flooring choice for a basement? Will my cats damage the floor?" for more advice about cork flooring.