So what does drainage have to do with a home. Well, each home typically is sitting on a piece of land - house boats excluded of course. The land or property the home sits on must have proper drainage for water to run off. The International Residential Code (IRC) defines drainage as follows:
R401.3 DRAINAGE
Surface drainage shall be diverted to a storm sewer conveyance or other approved point of collection that does not create a hazard. Lots shall be graded to drain surface water away from foundation walls. The grade shall fall not fewer than 6 inches (152 mm) within the first 10 feet (3048 mm).
Using that reference, the slope of the property away from the home must be 6 inches over the first 10 feet. Most properties will have sufficient room to allow for that drainage around the home. For homeowners, adding shrubs, trees, or other construction can change the drainage angle that allows the water to run off away from the foundation. Changing the slope and providing places where water can sit can cause problems to the foundation.
The Houston area deals with expansive soil which expands when it is wet. Allowing water to sit next to the foundation because the drainage has been affected can lead to heaving of the soil and the foundation. Check around the home looking for:
Places where water may be standing within 10 ft from the foundation
Evidence of trenching from water runoff from the roof
Places where grass or vegetation is dead and moss may be growing
Algae on the side of the home
These conditions may indicate excessive moisture levels from improper drainage (or plumbing leaks).
A notable area of concern is urban re-development in older neighborhoods. Older neighborhoods are often targets for new development. In Houston, this is often new residential homes using a common driveway. Lots are typically smaller and the homes provide large square footage. Many are 2 and 3 stories. See image below.
As can be seen in the image, space between the houses is limited. Often, just enough to meet fire code and access. These types of builds can have water runoff from one house being deposited on a neighboring property. In these cases, each property is recommended to have gutters installed to collect the water with downspouts that will deposit the water 5 to 10 feet way or to a local drain. As the picture above illustrates, there are sanitary sewer drains in the driveway that are used to collect runoff.
Boxer Inspections is your premier Professional Home Inspector. Call us at 281-783-3030 for all your home inspection needs.
Copywrited material. Not for use without written permission. Aug 2018
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