A 20-foot-wide-by-42-foot-long house has an 840-square-foot interior, while a 32-foot-wide-by-60-foot-long house has 1,920 square feet. Configurations A typical double-wide house is made up of two parts that are bolted together and are of equal length and breadth. The house width is the distance between its outer walls. The house depth is the distance from front to back inside the outer wall. The area of a double-wide house is calculated by multiplying its width by its depth. For example, a double-wide house with 42 feet for its width and 60 feet for its depth has a total area of 2,160 square feet. The volume of a double-wide house is calculated by multiplying its width by its depth by its height. For example, a double-wide house with 42 feet for its width, 60 feet for its depth, and 10 feet for its height has a volume of 5,280 cubic feet. The surface area of a double-wide house is calculated by adding the areas of all four sides: bottom, top, left, and right. For example, a double-wide house with 42-inch-deep walls needs to be shored up on the outside to prevent collapse. The crew would first have to demolish whatever is behind the house before they could measure the width of the structure. Thus, the surface area of a double-wide house cannot be determined until after it has been torn down.