One of the main sections of a home inspection report is grading and drainage. Grading has to do with how the soil is contoured around a house. For instance, there should be six inches of slope within ten feet on the outside of the house. Flat or inconsistent grading can contribute to poor drainage, which in turn can contribute to erosion and foundation problems.
How Grading Can Affect the Structure
As important as grading is, most of the houses I inspect in Waco and Central Texas have deficiencies in grading. It is often flat, or flower and shrub beds are bordered in flat areas alongside the house, restricting drainage. Frequently, the grading is too high along the house, providing an easy path for termites or other wood destroying organisms, or even water, to enter and damage the structure.
Erosion and Undermining
Almost as often, there is erosion at some stage doing slow and steady damage, or even severe damage. Water, like rust, never sleeps. The effects of erosion or poor drainage may not be noticeable from one day to the next, but time and water can cause undermining and damage. The picture below, taken in Bellmead, illustrates how improper grading and drainage can impact a structure. This was an extreme example, but water damage in Waco and Central Texas is common, where land is relatively flat to begin with.
Basic Drainage Systems
A well-designed house will have a well-designed drainage system that will direct water to places where it can do no harm. Part of that system is a gutter, which can catch the water and divert it into downspouts. If you have gutters, you should clean them annually, or as often as needed. Even with screens or leaf guards, gutters should be inspected and cleaned.
Organic debris and dust in gutters adds weight and slows the flow of water to the downspouts. Organic debris retains water that can accelerate rusting. It can even support plant life, like in the picture above. Because of this, it is very important to keep your gutters clean. Even downspouts can become clogged and may need to be cleared of debris, although not as often.
Additional Drainage Systems
Sometimes the lay of the land just doesn’t lend itself to ideal drainage, or grading along with gutters and downspouts does not provide enough protection for a foundation. In such cases, a foundation or “French” drain may be needed. In more extreme situations a sump pump may have to be used. It is best to have this done by a landscape and drainage specialist, because they will be more familiar with best practices that can provide you with a good result.
Grading and drainage is a serious area of concern that can affect the performance of your foundation, driveway and walkways. During periods of heavy rainfall or long wet periods like we often have, water can do a lot of damage. The job of any well-designed home is to minimize that damage, and grading and drainage should be carefully considered.