The American Society of Home Inspectors estimates that 60 percent of U.S. homes have wet basements, and 38 percent run the risk of serious basement mold. So whether you are finishing your basement for the first time or repairing it after a flood, play it safe. You may not be able to completely eliminate the risk of moisture from floods, seeping groundwater, runoff, condensation, and leaks. But you can discourage mold and mildew growth by choosing the right building materials that will not be damaged by moisture or support mold growth.

Here’s some advice to make sure your cave stays cozy and comfortable.

1. Determine the level of moisture in your basement and its source. 

Find out if you have a moisture problem before you renovate the basement. You may be able to see water draining from your walls or find damp spots, but often moisture is hidden. You need expert advice. Have an independent environmental testing company like RTK Environmental come in to help you determine where the water is coming from, and how much it is affecting the area. Often times, the problem can be fixed quite easily. Sometimes extending downspouts and angling them away from the home will prevent water from pooling around the foundation. Other times it is a matter of re-grading your yard to drain water away from the house.

2. Don’t use traditional building materials.

When wet, organic materials, such as drywall, wood, and paper, quickly become fertile breeding grounds for mold — a mold colony can sprout within 24-48 hours. RTK Environmental suggests using moisture-tolerant materials, such as green board and non-porous tile, especially in areas that come in direct contact with concrete, stone, or brick. If you have cracks in these masonry surfaces, patch them with hydraulic cement, which expands as it sets.

3. Install moisture-tolerant insulation on walls and floors.

Moisture-tolerant insulation protects the inside of your house from wide fluctuations in outside temperature, which often results in indoor condensation. A vapor barrier or rigid-foam insulation can be laid over foundation walls, followed by a metal stud framing and a non-cellulose wall finish. Many professionals recommend extruded polystyrene (XPS). If you choose XPS, please note that it is flammable, and needs to be covered with a thermal barrier, such as USG’s Sheetrock Brand Mold Tough Gypsum Panels.

4. Choose the right floor.

Before you lay down wall-to-wall carpeting to warm up your basement, consider that can trap moisture and cause mold to grow. Opt instead for breathable materials. Ceramic tile is the best, but can be costly. You can also try vinyl plank flooring, which has a wood-like appearance and can be clicked together, just like laminate. It makes installation easy, and repair equally easy. To make the room cozy, add an area rug rather than wall-to-wall. That way, if the rug gets wet, you can remove it to dry it out.