Consider a construction site that needs a storeroom to be constructed.
The site has a stack of concrete masonry blocks with nominal dimensions of 8 inches in width and depth and 16 inches in length used for the storeroom construction.
The site engineer has to design the storeroom to have the 16-inch length blocks placed precisely in the walls without having to cut the blocks.
The room's dimensions in the plan are 12 feet in length and 8 feet in width, measured from the outer corners.
The actual dimensions of the block are slightly less than the nominal dimensions. The block dimensions and mortar thickness together give a length of 16 inches.
Now, precisely 9 blocks are needed for the longer dimension of the wall and 6 for the shorter.
With this arrangement, the inner dimensions of the room become 10 feet 8 inches in the longer direction and 6 feet 8 inches in the shorter direction.
This practice avoids cutting the blocks and assures faster construction and a perfect finish.
