Basement Foundation

If your foundation does not have an adequate water drainage system to drain excess water and you do not have a sufficient water barrier on the exterior basement walls, you will have a damp or soggy basement and subsequently, this will lead to mold.

In basement foundations, water infiltration is controlled with perimeter drainage systems tied to either a sump pump or daylight drain and a waterproof membrane either sprayed on or mechanically affixed to the perimeter walls.

Although basements are popular with a great many people, they are not always feasible. In Florida, Georgia, Mississippi, Texas, etc. – sub-surface water is too close for portions of the year to control the possibility of water infiltration to the basement. So in these areas the preferred foundation has become the slab-on-grade.

Slab-on-grade is a foundation where you pour a mattress of concrete (usually with thickened portions at the perimeter and at interior load bearing locations). These are typically 4-6 inches thick and are both very economical and reliable and the easiest to control water issues with. They are preferred when dealing with low-bearing capacity soils and areas with water tables close to the surface (less than 10 feet). You will notice if these are the predominant type of foundation in your area. just look at the building lots in your area when construction begins and you will see what type of foundation is there.

Another issue with basement foundations or crawl-space foundations is the bearing capacity of the underlying soil and the expansiveness of the soil. Expansive soils expand as the take on moisture. If not accounted for, they can destroy a foundation is short order because of the pressures they exert on the concrete. They require special attention to drainage, backfill and sometimes the addition of caissons drilled into rock to support the walls. The caissons are drilled down to rock and the walls are supported on the caissons with a void underneath to allow for expansion of the soils. In any event, most basement foundations will have a concrete slab for the floor.

Another issue that is important to the safety and health of your family is to plan to mitigate Radon. Radon gas is now recognized as a very serious threat to the health of those who endure long-term exposure. It has been linked to lung cancer and other serious illnesses. It is also present in about 80% of the country. So you need to incorporate systems to mitigate its presence in the foundation.

Lastly, if the foundation is not laid out square, you will have problems with framing the upper portions to a square condition and thus problems with interior finishes etc. It is important to pick a competent and diligent concrete contractor to build the foundation and it even more important to have an engineer design the foundation to ensure that the proper type of foundation is put in place on the site you have chosen. Visit the American Concrete Institute website for further information.