by Alden Smith
One of the biggest problems, next to framing, in a basement remodel is dealing with moisture. Because the basement is below ground level, it already has two strikes against it. If the home has not been properly designed to start with, remodeling the basement can be a real pain if moisture is present in any form. Nothing is worse than doing a fine job of remodeling and then several months later having spots appear on the drywall. Not only is it expensive to replace, but the chances of mold forming is inevitable. Because some homes are built on a clay substrate, other problems can arise. Here, we discuss moisture problems in a basement remodel.
Proper Preparation - A Must
One thing that you must know is that there is no such thing as a dry basement. Even if you find no evidence of water stain or dampness, the very nature of the construction makes this so because the basement is below ground level. Even if the basement appears dry, there is still moisture n the form of water vapor. Try this - fasten a 24" square sheet of plastic on the basement wall. Remove after several days, and note the condition of the wall. If it is dry under the plastic, then water vapor is present. If wet, then there is water seepage in the walls from the exterior.
Begin by doing a proper inspection of your basement. If unsure what to look for, ask a contractor to assist you. Carry along a good strong flashlight for deeply shadowed areas. Look for water spots on the wall, and the presence of mold. Look for any overhead pipes that may have a slow drip. You don't want to cover these only to find later that they are seeping through ceiling tile or plaster ceilings.
You're way ahead of the game if you have poured walls in your basement. The contractor interviewed for this article informed me that in typical cement wall basements, water collects in the three holes of the cement block, and it is only a matter of time before moisture seeps through. The cause of this according to him is improper drainage techniques around the perimeter of the home. Check these blocks thoroughly, and if there is any sign of mold or water stain, you can bet that water is standing in the blocks. Even with poured walls, there is an introduction of water vapor due to the very nature of concrete.
Fixing Drainage Issues
Several methods are available, with the easiest to accomplish being done on the exterior of the home. Some of these things are as simple as re-routing a drain spout so it is not emptying along the perimeter of the home. Careful grading must be done to insure water runoff, and reworking the exterior runoff system is a must if not done properly. Proper grading ideally should slope down 10 to 15 feet from the house and have a drop of at least 6 inches.
Contractors recommend that if you live in areas with high clay content, such as in Colorado, that you do not plant large flower beds along perimeter walls. In an arid climate such as Colorado, these beds are watered frequently, and the composition of the soil makes for leakage. They instead recommend a deep gravel bed, and if you must have landscaping, use juniper trees.
In trouble areas, install a French drain. These are trenches installed around the exterior of the home to provide proper drainage. Many people think a French drain is installed with pipe, but the real French drain uses gravel. Be careful here - you don't want to install a French drain that will flood your neighbor's property. In extreme situations, the French drain can be installed in the basement floor. Plan on spending a good sum to have this done. Instructions for building a French drain can be found online.
Sealing Walls
Once you are sure that drainage issues are dealt with, seal the interior walls of the basement. If you find black stains indicating mold, use muriatic acid to clean them, hosing down well and insuring proper ventilation. Do this process a couple of times. Once clean, the walls can be sealed in several ways. Typically used is Drylok, but a more superior product is Xypex. Drylok is a latex based waterproofer, while Xypex, which is more expensive, relies on the presence of water to activate.
Always remember that a basement is never dry. You can deal with water vapor with a dehumidifier, and insure that proper venting of the dryer is in place. In newer construction that is much tighter than older homes, provide proper ventilation to the interior. Always deal with moisture before you begin a basement remodel.
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