Q: We have a problem with moisture in our basement. The walls are damp and mildew is a constant problem. I have used household bleach mixed with warm water to remove mildew, but it returns within months. We would like to make better use of this space by converting the basement into a recreation room. Do you have any suggestions on how to fight the moisture so we can use this area?
A: Moisture problems in basements are a widespread concern among our readers. Although I have covered various aspects of this problem previously, the suggestions are worth repeating. There's also information on some new products that can help combat this problem.
A thorough inspection of your house's exterior and foundation is essential before dealing with the basement interior. Make sure all outside gutters and drains are free of leaves and debris. Check for leaks in downspouts and gutter seams. Make sure the gutter drains carry water away from your house.
Rainwater trapped near foundations is a major source of moisture problems. The ground should be sloped so that water flows easily away from the house. If necessary, fill in low spots around the foundation with gravel and soil, caulk around basement windows, extend downspouts and replace splash blocks.
Water pressure, or hydrostatic pressure, is caused by water being trapped between the soil and wall, pushing against the foundation and entering through the basement's foundation wall.
Once you are satisfied that you've directed water away from the house, you're ready to begin your project inside the basement. Proper preparation of your walls, whether they are poured concrete or concrete block, is essential before waterproofing.
Bondex Co. has introduced a complete line of waterproofing products that can protect your home from moisture and water damage, both above and below grade. Before dealing with waterproofing products, your first step is to use a cleaning solution and a wire brush to remove all dust, dirt and grease. Next, scrape away all loose mortar. Repair holes and cracks with Bondex Quick Plug Hydraulic Cement, following directions carefully. This is a fast-setting cement and expands in the hole or crack for a tight seal. It will stop the flow of running water and seal cracks and holes, even when water pressure exists behind the wall.
After patching cracks, holes and defects, examine the wall for any white or grayish powder on the surface. This is known as efflorescence--soluble salts forced through the wall, due to water pressure from behind the wall. Remove efflorescence using Bondex Concrete Cleaning and Etching Compound, following directions carefully.
You also can use a solution of muriatic acid, mixing one part acid to nine parts water, but the convenience and ease of a commercial product is preferable. Usually, 12 ounces of the Bondex crystals mixed with one gallon of warm water will remove efflorescence, using a stiff bristle scrub brush. Rinse with clean water and let dry completely before applying any surface coatings.
If your walls have been painted with either an oil-based or latex-based paint, you will have to sandblast all of the paint, down to the bare masonry surface. You will be using a cementitious coating (cement-based paint) that must be applied to a bare masonry wall to have a waterproofing effect.
There are a number of cement-based paints on the market. There are three products in the Bondex line. The water-based Mildewproof Waterproof Cement Paint is easily applied with a brush, roller or sprayer. Two coats are recommended, and clean-up is with water.
The solvent-based, ready-mixed Waterproof Cement Paint is similar but clean-up requires a solvent. There also is a Waterproof Cement Paint Powder that can be mixed with water or Bondex Bonding Liquid for application to a wall that has been dampened.
A coarse, fiber scrub brush with a handle should be used to work the material into the pores of the masonry surface. Two coats are required with 24 hours between coats. After 30 days, the powdered paint can be painted with an acrylic-based paint to any desired shade.
Both ready-mixed and powdered paints are "tintable," and after 28 days of curing, these waterproofing products can be painted over with oil-based or latex-based paint to achieve any desired color.
If you still are concerned about mildew from atmosphere moisture, use a mildewcide in the finish-paint coatings or choose Zinsser's Perma-White Paint, which is guaranteed to protect against mildew.
If you are unable to locate Bondex products in your area, contact Bondex International Inc., 3616 Scarlet Oak Blvd., St. Louis, Mo. 63122, or phone 1-800-225-7522.
Q: I have a problem with a wood-paneled wall. When I went to rearrange some pictures and paintings, I was surprised to see that the wood where the pictures hung was much darker than the surrounding surface. Is there anything that can be done to alleviate the discoloration?
A: You have a problem only time will erase. Natural light can cause wood paneling to lighten or darken, depending on the type of wood. This process will continue gradually, and there is no way to reverse it short of stripping the wood, sanding it and applying a new finish. Sometimes a thorough cleaning with a product such as Murphy's Oil Soap will help because it removes any dirt and grime that may have built up on the exposed wood. If you remove the pictures, the wood exposed to light will, after a few months, begin to attain the same color as the surrounding wood.
One way to avoid this problem is to periodically move pictures and wall hangings on new wood paneling. You won't have to continue this forever, because most of the color change caused by air and light exposure will occur within the first few years after installation.
Send e-mail to firstname.lastname@example.org or write to Here's How, Copley News Service, P.O. Box 120190, San Diego, Calif. 92112-0190. Only questions of general interest can be answered in the column.