In basement slab calculation, what is CLP?

• A. 55 m
• B. 23 m
• C. 34.8 m
• D. 119.7 m

Answer: (A)

CLP is the length measured along the centerline of the basement walls—the path you would follow if you walked around the slab right through the middle of each wall thickness. This centerline length is used for layout and quantity calculations, such as estimating formwork and the perimeter for pouring concrete around the slab. In this problem, the dimensions given lead to a centerline perimeter of 55 meters, which is why that value is the right one for CLP. The other numbers would correspond to paths that aren’t through the wall centers (like exterior or interior perimeters) and thus don’t represent the CLP.