Building stairs can require detailed measurement, but if you have the construction skills to build the steps themselves, do not let the calculations intimidate you. A few basic measurements can help you judge how much total room you need for a flight of stairs. There are also a number of tricks you can use in tighter spaces to still have enough room for your stair project. The basic measurement is a comparison between the rise and run of your stairway and the size of each step.
Headroom and Width
Headroom refers to how much room you need between a ceiling and the stairs at any point. This becomes especially important when you are building stairs down to a lower level, such as a basement, where the stairs pass through a floor. The general minimum headroom is 6 feet, 8 inches. Anything shorter will feel uncomfortable and make it very difficult to negotiate the steps with large objects, such as furniture. The width should be at least 3 feet.
Rise and Run
The rise is how far up your stairs will go, while the run is how far out they will go. Measure the rise and run, convert them both to inches, and multiply them together. The rise of a good step is considered to be somewhere between 6 3/4 inches and 7 1/2 inches. Choose the higher step if you have less room, and the lower step if comfort is more important. Divide the multiplied rise and run by this ideal step, which shows how many risers or steps you need. Round the number, subtract 1 (for the last step) and multiple the result by your ideal run to find out how much space you will need for the stairs.
Spiral staircases do not need to be rounded. They too can be made from square-shaped steps placed at carefully determined angles. Spiral staircases can be ideal if you are very short on room and need a staircase to fit in an awkward area. The stair area must be 5 feet by 5 feet to meet modern building requirements.
A landing is a useful compromise between a spiral staircase and a traditional, straight-down stairway. The landing is a short platform construction halfway down the stairway. At the landing the staircase can switch to a right angle from its original direction, allowing you to install the staircase when you do not have enough space going only one way. This leads to two separate rise and run calculations.