In many areas across the country, the basement or lower level might get damp during portions of the late spring and summer. Basement dampness is a normal phenomenon, occurring because cool air cannot hold as much moisture as warm air, so it is not necessarily an indication of a water problem. During late spring and summer, the temperature of the air in the basement or crawl space is always cooler than the outside air. Consequently, when outside air infiltrates into the basement through open windows, doors, cracks or joints, the temperature of air drops. Because this cooler air cannot hold as much moisture, it results in a higher relative humidity of the air that entered the basement.
Depending on temperature, as well as the amount of moisture present in the air, some moisture might condense in cool surfaces such as foundation walls and cold-water pipes. In some cases, water droplets on the foundation wall caused by condensation are incorrectly diagnosed as caused by seepage through the wall. A damp-wet foundation wall can be easily checked to determine whether the condition is caused by seepage or condensation. Just fasten a small piece of aluminum foil to the foundation wall, and seal the edges of the foil to the wall, using wide strips of an adhesive tape. After at least 24 hours, examine the surface of the foil. If it is moist, the condition is caused by condensation. If the foil surface is dry but the area behind the foil is damp, it means the condition is caused by moisture seeping through the foundation wall from the outside. If both the foil and the wall are damp, the condition indicates both seepage and condensation.
Crawl space or basement dampness should be controlled, because it can produce conditions resulting in mold growth and decay fungi. Generally, dampness can be detected by musty odors or a clammy, close feeling. In the drier areas of the country, normal basement dampness (caused by condensation, not seepage) can be controlled by opening the windows and ventilating the area. On the other hand, in areas where the climate is hot and humid during the summer, the benefit gained by ventilating the area is lost by the introduction of moist air into the basement. In such areas, the dampness in the lower level can be controlled with one (or more) good dehumidifier for your basement.
Most dehumidifiers have a humidity control that automatically shuts the dehumidifier off when the moisture content in the air reaches a preset level. Depending on the weather and the size of the unit, the dehumidifier might have to run for many hours a day in order to wring out sufficient moisture from the air so as not to lead to air quality problems.
How to Reduce Basement Dampness
A basement adds storage space or living space, so it is a desirable addition to a home. When a basement is damp, however, it can become a major problem. It creates a musty smell all throughout the home reducing indoor air quality, and it can also create problems with mold. You can opt for a basement waterproofing but this type of service is generally expensive and in many cases, you can reduce basement dampness and correct the problem in a number of other easier and cheaper ways.
Repair Settlement Cracks to Reduce Water Problems
Even in newly poured concrete, cracks can develop once homes settle. If a settlement crack has developed, moisture can seep in when it rains or when snow starts to melt. If the cracks aer due to settlement, they are easy to repair even without professional help. Using a cold chisel, a mallet, patching cement or other expanding sealant, and a putty knife, start bevelling the crack and slightly widening it with the cold chisel and mallet. This will help the patch or sealant bond with the cement. Once the crack has been prepared, apply ready-mixed patching cement or expanding sealant according to product label instructions. Push it into the crack as it dries, using the blade of the putty knife, and apply more to the surface. Smooth the surface with the putty knife to make a clean repair. Once it dries, moisture should no longer be a problem.
Waterproof the Walls
To solve water problems in basements, professionals often dig trenches around basement walls. The walls are then covered with waterproofing material that alleviates interior moisture. If the moisture problem is minor, however, digging a trench around the foundation and waterproofing exterior walls might be an overkill. A better solution might be to visit your local home improvement store and get some waterproofing paint. It will help reduce moisture in the basement, and also help seal out existing odors that come from basement walls.
Reduce Seepage by Extending Downspouts
The roof of the home is one of the main sources of basement dampness and moisture. When it rains or when snow and ice melt, the moisture runs off the roof and into eaves troughs and downspouts. If the eaves troughs leak or if downspouts are not far enough away from the foundation of the home, moisture can seep through the smallest crack or around basement window frames. In order to divert water and reduce the amount that reaches the foundation, extend downspouts at least six feet from the home.
Install a Rain Barrel to Reduce Moisture Naturally
If a particular area of the home is causing most of the moisture in the basement, install a rain barrel instead of extending the downspout. A rain barrel is a great way to catch water from the roof that might end up in the basement. No special equipment is required, just buy a plastic trashcan with a tight-fitting lid and cut away the downspout at the proper level, then cut away an area of the trashcan lid to accommodate the downspout. Cover the trashcan rain barrel to keep out debris and insects. You can later siphon the water collected and use it for watering plants.
Reduce Condensation
Unwanted moisture below ground is not caused just by cracks in the basement walls and insufficient water diversion. Pipes can generate a considerable amount of condensation, which drips on floors and runs down piping and into walls, where mold and mildew can form. Wrap pipes with insulation foam to reduce the basement moisture. It is relatively cheap and easy to install.
Dryer Ventilation
To avoid moisture problems, a dryer must be properly ventilated, including a dryer located in the basement. If it is no properly vented it will add moisture to the air and it will settle on walls, ceilings and floors, creating serious moisture problems. Running a dryer that is not properly ventilated will immediately cause moisture issues and odours in a basement, and it is essential to make sure it is adequately vented to the outside.
Use a Good Dehumidifier to Reduce Moisture in the Air and Improve Indoor Air Quality
Once you manage to control the sources of moisture, the easiest way to further reduce moisture in the air and improve indoor air quality is with a good dehumidifier. A dehumidifier can pull gallons of moisture out of the air each day, and in a basement with moisture problems it is a great way to reduce it. Purchase a good dehumidifier for your basement. If possible, set it up to empty into a basement drain. Automatic draining will ease your job significantly, and will keep the dehumidifier running as often as needed to reduce moisture in the basement.