What Causes Moisture in My Basement in South Carolina?

Jul 7, 2017

Categories: Foundations

As the experts in foundation repair, located in Charleston and Columbia, South Carolina,CNT knows that by the time you notice moisture on your basement walls, chances are that the water had been there for quite some time and the home’s foundation damage has begun. Water is one of a foundation’s worst enemies. In this article, we will define hydrostatic pressure, the ways in which water can find its way into your basement and the damage it can cause in South Carolina.

What is Hydrostatic Pressure?

Moisture on basement walls occurs most often due to the force of hydrostatic pressure which is the pressure created by standing or resting (“static”) water (“hydro”). While concrete is a relatively solid material when dry, it is not solid in the same way that stainless steel or marble is. It is not impervious to moisture.

As concrete dries, water vapor from the concrete mixture evaporates from the slab, creating small cracks/pathways. These pathways remain open until properly sealed, and can trap water in the concrete. Newer, high-strength concretes can resist higher levels of pressure than older mixtures, they still can be susceptible if cracks form or hydrostatic pressure builds.

For concrete basement walls to be impacted by hydrostatic pressure, they must be below the water table. Water flows downhill, and home sites cut into a hillside have a greater risk of experiencing hydrostatic pressure if water is not redirected. Poor drainage may cause water to pool against a concrete foundation but generally will not build the volume to cause problems attributable to hydrostatic pressure.

How Can Water Accumulate in My Basement in South Carolina?

It is important to identify the correct source to correct the problem.

Water Supply Sources. Sprinklers, plumbing, city mains and other water supply lines may be a source of moisture if they break or if a joint fails. If this occurs in a location with poor drainage or very dense soil, water may be in constant contact with the concrete and increase its internal moisture content, or relative humidity (RH). The pressure formed by a burst pipe is technically a type of hydraulic (or a mechanical force) pressure.

Inadequate Installation. Some installation problems that can result in excess concrete slab moisture may include a vapor retarder with insufficient or poor “perm” (permeability) rating, insufficient site evaluation or geotechnical survey to identify natural water sources, excessive troweling that prematurely seals the slab surface, or surface membranes applied before the slab was adequately dry.

Improperly Dried Concrete. In cases where flooring failure is attributed to excess moisture, it is important to be sure that the slab was adequately dry before flooring was installed. Installers intent on meeting a construction deadline, or those who use surface-only test methods like calcium chloride testing, may not have had accurate moisture content data to base their adhesive or flooring material choices on. Only RH testing can adequately determine the true moisture conditions of a concrete slab and inform both schedule and flooring decisions.

How Can Water Damage My Home’s Foundation in South Carolina?

Heavy rainfall. Heavy rain is one of the most common causes of flooding. Excessive water from short periods of rain will overload your basement waterproofing. The water saturates the ground around the basement to push inside through the foundation wall cracks.

Water-saturated soil around the house. Loosely packed soil adjacent to the foundation may absorb a large volume of water. The continuous presence of water into the foundation may penetrate the basement. Make sure gutters and downspouts are functional. Also, landscape should be graded to divert water away from the foundation. Indoors, a basement sump pump provides protection against acute inundation.

Lawn grading. Grading is the slope of your lawn and should always slope away from your home to direct the excess rain water into the sewer. A simple way to check your lawn’s grading is to walk around the house during or after a rainfall and see if you can find water pooling around the foundation. The grading of the soil around the entire perimeter of the house should slope down at least 6 inches for the first 6 – 10 feet of horizontal distance. This will help to ensure that any groundwater will be channeled away from the house

Overflowing gutters. Keeping gutters clean of debris such as leaves and branches should be a part of the routine maintenance of your home. Depending on the surrounding trees, gutter cleaning may be required a few times a year. The installation of gutter guards helps to prevent leaves from getting into the gutters and creating a waterfall. Gutters should be pitched slightly toward their downspouts.

Overflowing downspouts. Water overflowing from the gutters running down next to or on the home’s foundation is another reason for basement flooding. The running water could be eroding soil from under the house which can lead to cracking of walls and ceilings. A concrete or plastic splash block may be all you need under the gutter downspouts. Splash blocks absorb the force of water cascading down from the roof and spread out the flow so it doesn’t erode a hole into the soil next to the house. The blocks also direct the water farther from the foundation.

Downspout distance. As previously mentioned, rain water is the most common source of basement flooding, therefore, it is imperative that downspouts should be extended at least ten feet from your home. Ten feet is the minimum distance needed to funnel the water coming off your roof. If your downspout cannot reach the ten-foot minimum then we would encourage you to purchase downspout extensions.

The downspout extensions should effectively channel the water from the house. This will help to ensure that the water will not seep back into the basement. If the soil slopes toward your house, extending the gutters will not be enough to keep water away, so grading becomes even more important.

Your home’s foundation could be susceptible to water damage without you knowing. Water damage to a home’s foundation can be irreparable if not caught in time. Contact CNT to learn more about water sources and the ways in which it can destroy a home’s foundation.

CNT offers solutions for the residential foundation, commercial foundation and crawlspace problems. Get your free estimate today! Fill out our form or call: 843-405-7022