Draining a Home - How to Spot Drainage Issues that May Affect Foundations

Proper home drainage is essential to long term home maintenance and the continued performance of the foundation. The foundation is the structure of the home that carries all the weight of the structure and transfers that weight to the ground. If the area around the home does not drain correctly, problems with the foundation can occur. In this article, Boxer Inspections will provide some information and guidance on the proper method of drainage and how homeowners can evaluate the areas around their home.

The Houston area has a type of soil known as clay type. Below are a few characteristics of Clay Soils from the BBC:

· Feels lumpy and sticky when very wet

· Rock-hard when dry

· Clay drains poorly

· Few air spaces

· Warms slowly in spring

· Heavy to cultivate

· If drainage is improved, plants grow well as it holds more nutrients than many other soils


A key issue with Houston clay soil is rain causes the soil to expand. If this expansion occurs against a foundation, the condition known as “Heaving - to cause to swell or rise” takes place. Heaving soil expands and forces the foundation upward. This put a tremendous load in the foundation and subsequently can cause damage to the exterior and interior.


The opposite condition also exists with clay soils, know and settlement. When this condition occurs, the foundation sinks or settles into the ground. When the home settles the same types of damage can occur on exterior and interior finishes. A majority of the time, the damage is cracking. In some cases, exterior windows and doors will become difficult to open/close.

Proper Drainage

In order to help prevent these conditions, proper drainage is very important. The International Residential Code recommends ½ inch of negative slope on the soil per foot for the first 6 feet. That means the soil must drop 3 inches over that 6 foot span. Homeowners should inspect around a home using a straight edge and angle finder to document the minimum slop is being maintained. Using an angle finder, the angle down should be 2.4 degrees or approximately 2.5 degrees.

Additionally, homeowners should identify and correct any spots where water puddles for extended periods of time. Water should drain or evaporate from a location within 2-3 days after a heavy rain. If there are locations that do not drain well, trenches can be dug to draw the water away or a piped drain can be installed.

If the home is equipped with gutters and downspouts, ensure the downspouts deposit runoff at least 5 ft away from the foundation. The use of a solid object to diver the water stream is also effective such and a stone, concrete block or other mechanism to help guide the water to where it needs to go.

If in doubt about the performance of your foundation or drainage, you are welcome to call (281-783-3030) or go online to schedule an inspection with Boxer Inspections. We would love to help!

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Tel:  281-783-3030

Fax: 281-581-0296

225 Matlage Way 
Suite 1383

Sugar Land, Texas 77487