Can a cork floor in the basement hold up if there would be excess water?

Question

Can a cork floor in the basement hold up if there would be excess water?

Asked by Lynne Hamm

We would like to put a cork floor in our basement but worry about chance of excess water entering the basement. If this would happen and we shop vac it up would the cork dry out, or need to be replaced.

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Answers

Joel Hirshberg's picture

This is a great question because the common notion about cork is that it might mold andmildew if it gets wet. Mold and mildew will grow as long as there is moisture and food.

  • However, cork poses a serious challenge to mold growth because of its nearimpermeability.
  • Cork is hydrophobic which means it is difficult to wet.
  • One cubic inch ofcork is said to contain millions of tiny cells of suberin which is a gas that helps insulate and protect cork from physical or biological intrusions. It not only resists moisture but it also is resists fire and denting.

Generally speaking it is difficult for mold to grow on the surface which is why cork has beenused as stoppers in wine bottles for centuries. Have you ever seen mold grow on a wine stopper? No. How about a cork fishing bobber? Ever see a moldy one? Nope.

Cork flooring is an engineered product

We don't want to give the impression that you can put your cork flooring underwater andnothing will happen. Most cork flooring is an engineered product that has a high density fiberboard (HDF) core that is made of recycled wood fibers.

  • While most companies use an exterior grade HDF, the best ones impregnate it with wax around the perimiter.
  • Even with this, it the HDF core is subject to mold in the presence of excessive moisture.

The surface of most cork floors is typically coated with a polyurethane or acrylic finish.While these are very durable and long lasting under normal foot traffic and normal damp mopping, they will lose adhesion if they are left under water for long periods of time.

Falling Water

Having said all this, it is only fair to provide an example of one of America's greatestarchitects, Frank Lloyd Wright. Two years ago my wife and I toured his famous Falling Water home in Pennsylvania. We were surprised to see the original cork used on the floors, walls and inside the showers of almost all six bathrooms. Considering that this home wasbuilt in the 1930's, what was really shocking was that there was no evidence of mold ormildew anywhere.

I am fully aware that this is a historic home and is probably cleanedweekly, but the fact that Wright used this product in the frist place gives one confidence thatthis product will hold up in damp conditions.

Comparing cork's performance to bamboo and linoleum

Here's one more story that is worth mentioning. Our company typically displays at tradeshows and one year the venue was outdoors in a quanset hut in August. The temp was about 95 and the humidity was about the same. Everyone was perspiring and the concretefloors were so wet you could see pools of water everywhere.

We had three types of flooringdisplayed directly on top of this floor; bamboo, linoleum and cork.

  • The bamboo andlinoleum were covered with water and the cork was dry as a bone.
  • The architects andbuilders that visited our booth could not believe their eyes when we pointed out how dry itwas.
  • We reasoned that the thermally insulating quality of cork actually blocked the cold concrete from transferring through and condensing on top of the cork.

It was a realexperience that taught us some lessons and helped us sell cork that day.

Can cork hold up?

Back to your question: Cork generally does not get wet as it seems to shed moisture verywell.

  • But under prolonged contact it might absorb a small amount.
  • Can it be dried out? Icertainly believe it can dry out with fans, heaters or dehumidifiers.

I would spend someserious time and attention on preventing this moisture problem in the first place.

  • Should you use your cork flooring in a damp basement, I would still advise using moisture barriers such as 6 ml plastic underneath the flooring to help control excessive moisture.
  • In the event of excessive moisture you should try to mitigate it with ventilation and dehumidification.

Non-toxicpenetrating concrete sealers such as GBS Penetrating sealer are helpful as are good cracksealants such as M-1 made by Chemlink.

If basement moisture is a persistent problem, you may need tolook at the drainage and landscape around your home. While excavation may be costly, itwill avoid other more serious problems with your foundation.

Further questions or comments write to: info1@greenbuildingsupply.com or call800-405-0222.

For more information:

Read "I just finished remodeling my basement. Can you help me choose mold-resistant flooring?" a Q&A answered by Mary Cordaro.