S.C. Code Ann. § 5-25-920: Rows of frame houses.

In rows of frame houses, the dividing walls or partitions between houses shall be built of brick, terra cotta, concrete or other incombustible material or they may be built with four-inch studs, filled solidly with brickwork laid in mortar or with other incombustible material. If lath be used on such partitions, it shall be metal lath. Such dividing partitions shall rest on masonry walls and shall extend to the underside of roof boards. A flush mortar joint shall be made between the roof boards and the wall or partition. In rows of more than three houses, every alternate division wall or partition shall be constructed of solid brickwork not less than eight inches in thickness. Buildings with wooden framework, clad with sheet metal or veneered with brick, shall be classed as frame buildings.