Roofing and roofing materials shall be sold either by the "square" or by the "square foot". The term "square" shall mean the quantity of roofing or roofing material that, when applied according to directions or instructions of the manufacturer, will cover an area of 100 square feet exclusive of side laps or side joints. In case of roofing or roofing material of corrugated design, the side lap or side joint shall be one full corrugation.
2 Miss. Code. R. 1-4-09-102.01