A staircase takes up a lot of room on both the lower and upper floors, requiring careful consideration of the location. Plan a typical staircase for a house with an 8-foot ceiling at 3 feet wide with between 9 and 10 feet of horizontal floor space. Allocate the 30 square feet above and below the stair for access between floors. You can enclose the area beneath the staircase on the first floor for extra storage, as most of it has restricted headroom.