So what's radon gas? According to the EPA, radon gas exposure is the leading cause of lung cancer after cigarette smoking. It's an invisible and odorless radioactive gas and is produced during the nature disintegration of radioactive heavy metals uranium and thorium, which are dispersed throughout the Earth's crust. Dig up the top 6 feet of an acre of land and you will find about 50 pounds of uranium. Each year, the average person receives more radiation from radon at home than from all other natural and man-made sources combined.
This radon gas naturally moves into the disturbed soil and gravel bed surrounding building and home foundations and then through the cracks and pores in the concrete. Radon is also water soluble and gets indoors by water infiltration as well. Water is drawn indoors by the capillary action of the pores in concrete or pushed by hydrostatic pressure (seepage), usually during heavy rains. If you're thinking your current foundation coating and vapor barrier will protect your basement, keep reading...
Concrete is highly alkaline (ph. 9-11), and these alkalis disintegrate exterior waterproofing coatings, which are only guaranteed for 5 - 10 years. The plastic sheet under the concrete slab (used as a vapor barrier) gets eaten by lime from the concrete. As soil and gravel settle, water and soil gases pool in the void right underneath the slab.
Water migration gradually leaches the capillaries, and makes the concrete more and more porous. As concrete ages, the seepage of liquid water, water vapor, and radon gas steadily increases. Water carries dissolved alkalis from the concrete and the soil. Water vapor condenses on cool surfaces or when trapped under a covering, and activates the alkalis in the concrete.
The alkalis dissolved in the water attack fatty acids in paints and adhesives. Therefore, the common surface sealers typically used will eventually peel or blister. If you install floor tiles, sheet vinyl, or linoleum, it will trap moisture and the glue will disintegrate. The alkalis even attack carpeting, floor coverings, and the concrete itself. Lime from inside the concrete forms efflorescence, a whitish mineral powder which easily lifts paints and floor tiles. You've probably seen this white powder before on basement concrete walls.
Even if your basement looks dry, moisture is pouring in as an invisible vapor and by evaporation of water seeping through capillaries. It might surprise you to learn that the basement is by far the largest source of moisture in your home, evaporating 15 - 18 gallons of water a day into your home. This moisture promotes molds, mildew, dust mites, and other biological air contaminants which cause allergies, asthma, and other health problems.
Mold thrives in carpeting, upholstered furniture, drywall, wood paneling, or in other words, most of what will end up in your finished basement. Dehumidifiers are commonly used in basements to control the moisture and humidity, but they consume lots of power and release that energy as heat which adds to the air conditioning load. In the long run, dehumidifiers draw in more moisture from the ground through the porous concrete, making it more porous and accelerating it's deterioration.
The description above isn't encouraging, but these are real issues which must me taken into consideration when finishing a basement. If the problem outlined above is not properly addressed at the very beginning, then the entire project has potentially been compromised and future problems are likely. Beyond the possibility of tearing our the basement within a few years time, there is the greater health risk of exposing your family to mold, mildew and radon gas. This is preventable.
The Southern Basement Company uses an exclusive commercial grade deep penetrating concrete sealer which penetrates several inches into the concrete. This sealer reacts with the lime and alkalis, expands into the capillaries and hardens as an insoluble material. This product is environmentally safe, non toxic, non hazardous, non flammable, and most importantly, all of the problems listed above are addressed via this one application. This is the first step in our basement finishing process, and it sets us apart from the other companies out there. Yes, we could finish a job a little faster and reduce our costs by omitting this one step, but we want your basement to last a lifetime. Besides, it's the right thing to do.