Grading and Drainage:  It is even more important than you think!

by Matthew L. Motes

Matthew L. Motes is a partner in the Fort Worth office of Shackelford, Bowen, McKinley & Norton, LLP, and can be reached at 682-339-9870 or [email protected]. The firm also has offices in Dallas, Austin, Houston and Nashville with a strong foundation in all areas of construction law and construction/design defect litigation.


It is a fact in North Texas that no matter how deep the piers or wide the grade beams, foundations will move.  However, the simplest way to avoid problems is often the most overlooked, such as draining water away from the foundation. This becomes a homeowner’s obligation after the home is occupied and for years into the life of the home. Thus, it is everyone’s responsibility to ensure that there is always position drainage away from all sides of the foundation.

There are two major building codes that govern this standard.

First, there is the International Residential Code (the “IRC”)[1]. Second, there is the more general International Building Code (the “IBC”)[2].  While at times these two codes can contradict each other, on this issue they are consistent.  Both generally require that the slope away from the foundation is six inches in 10 feet of fall.   Said another way, the slope away from the foundation is required to be five percent in the first ten feet.  However, the IRC does contain an exception to the rule.  If a house is being built where five percent slope cannot be achieved in 10 feet (for instance with a zero lot line), then the code can be met by achieving position slope enough to drain the water into a pipe or drain to take the water away from the foundation. 

First, the IRC also requires that there is four to six inches[3] of clearance above the finished grade and the top of the foundation.[4]   This is for two basic reasons:  (i) not to cover up the weep holes;  and (ii) eliminate a way for bugs to enter the house.   There is a third reason—so that you can easily achieve a six inch slope away from the foundation. 

Second, as you know, many times at the end of construction due to budgetary or other considerations, landscaping is removed from the builder’s scope.  This can be a huge trap if the builder is not paying attention.  Therefore, make sure to take photos of the elevation when the dirt contractor has finished so that you can establish the final grade and slope, in case the later installed landscaping alters that slope.   Photographs and video are a start but using a laser level to establish the exact measurements will be the gold standard later if you have to defend yourself in court or arbitration.   

Grading and Drainage

[1] R401.3 Drainage

[2] R1804.3 Site Grading

[3] Masonry veneer- at least 4”;  Others- 6”

[4] R404.1.6 Height Above Finished Grade

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