South Carolina Engineering and Permit Requirements

In general, any retaining wall that is four feet (4’) in height or greater (measured from the bottom of the footing to the top of the wall), and any retaining wall supporting a surcharge or impounding Class I, II, or IIIA liquids, whether site-built or modular, must be designed by a Registered South Carolina Professional Engineer. A licensed contractor must obtain the permit and walls over six feet (6′) in height require a “third-party” SC licensed “Special Inspector” to inspect the construction of all engineered retaining walls.

Spartanburg County, York County, Lancaster County, and Horry County are a few of the counties that have been confirmed to follow the above requirements.

The City of Greenville, SC requires a separate building permit application for all retaining walls, but only requires engineering per the statement above.

References:

The 2021 South Carolina Residential Code (IRC) states:

R404.4 Retaining Walls

Retaining walls that are not laterally supported at the top and that retain in excess of 48 inches (1219 mm) of unbalanced fill, or retaining walls exceeding 24 inches (610 mm) in height that resist lateral loads in addition to soil, shall be designed in accordance with accepted engineering practice to ensure stability against overturning, sliding, excessive foundation pressure and water uplift. Retaining walls shall be designed for a safety factor of 1.5 against lateral sliding and overturning. This section shall not apply to foundation walls supporting buildings.

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