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Basement Waterproofing - Bad Grading and Basement Wetness

Monday, February 6th, 2023 by Aaron Stull

Bad Grading and Basement Wetness - Image 1Having poor grading conditions around a home can cause serious problems, such as basement leaking, high humidity, smells, odors and, if not corrected, serious foundation damage. The Pennsylvania residential building code outlines specific requirements for grade height and slope around a home in order to prevent these types of issues. Sadly this standard is often missed. In the Pittsburgh area, we observe many homes where this standard is not present every day. Even more unusual is the pervasive problems in newer neighborhoods, where code enforcement would have been more established and robust at the time of construction than with older homes.  When these requirements are not met, the risk of basement wetness and foundation damage increases.

Grade height refers to the height of the soil surrounding a home in relation to the foundation. A “positive grade” refers to one where the water runs away from the home, whereas a “negative grade” is one where water runs towards a home or building. The Pennsylvania building code requires that the grade height should be sloped away from the foundation in order to prevent water from pooling around the foundation and potentially leaking into the basement. A minimum standard is required to prevent water from flowing towards the foundation. If the grade height is too low, it can result in water flowing back towards the home and water collecting around the foundation. This increases the potential of water seeping into the basement, leading to basement wetness and potential foundation damage.

The slope of the soil around a home is another important factor to consider when grading around a home. The slope should be gradual and consistent to allow water to flow away from the foundation without pooling. If the slope is too gradual, it can cause water to flow too slowly and some may run towards the foundation, leading to basement wetness and foundation damage.

It's also important to consider the types of materials used in the grading process. Gravel, rocks, and other porous materials are not suitable for grading around a home as they allow water to penetrate through to the soil and potentially reach the foundation. Instead, clay and other non-porous materials should be used to prevent water from penetrating through to the soil and reaching the foundation. This is best practice.

Another factor to consider is the presence and operation of gutters and downspouts around a home. When done correctly, these systems are designed to channel water away from the foundation and into a sewer or other area far away from the home. If they are not installed or functioning properly, water can collect around the foundation, leading to basement wetness and foundation damage.

In addition to the requirements outlined in the Pennsylvania building code, there are several other factors that can contribute to basement wetness and foundation damage. Concrete flat work around a home that has sunk over time towards the home can artificially create a negative grade towards the home and bring water against the foundation. Additionally, adding non-permeable surfaces around the home, like driveways, walkways and other added items, can change how water flows around the home and inadvertently cause basement leaking and other foundation problems. The design of these items should account for water management and drainage to prevent such occurrences from happening.

So if you are experiencing basement wetness, the first step is to have an expert like Keystone Basement Systems provide a free site inspection to evaluate the grading conditions and determine a repair plan to correct the basement wetness and leaking problem that you are having.  


About the author
Aaron Stull is a second generation foundation repair specialist from the greater Pittsburgh, Pennsylvania area.

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