Staircase Volume

… Staircase As A Stage and Open Stairs will tell you roughly where to place the various stairs, both indoors and outdoors. This pattern gives each stair exact dimensions and treats it like a room so that it becomes realistic in the plan.

We are putting this pattern in the language because our experiments have shown us that lay people often make mistakes about the volume which a staircase needs and therefore make their plans unbuildable.

NEW: We are also adding a calculator function that will allow you to enter your own working dimensions and find out how much room to include for the staircase volume in your plan.

Discussion:

Do not assume that all stairs have to have the "standard" angle of 30 degrees. The steepest stair may almost be a ladder. The most generous stair can be as shallow as a ramp and quite wide. As you work out the exact slope of your stair, bear in mind the relationship: riser + tread=17.5 inches

Here are some examples of the stairs which people who are not used to building, draw, or think of, when they try to lay out houses for themselves.

The simplest way to understand a stair is this. Every staircase occupies a volume, two stories high. If this volume is the right shape, and large enough to give the stair its rise, then it will be possible to fill it later, with a stair which works.

Calculator:

(NOTE: Change the first two values to get your results below.)

The width of the stairway volume is typically at least three feet, plus any wall thickness.

You will want to add clear space for a landing at each floor - at least 3 feet by 3 feet. This can be part of the room at each floor, or a separate part of the staircase volume. (This is often the case when the stairs are shared between adjoining private spaces, such as apartment units.)

If you want your stairway to turn to form an L, U or C, you should add landing areas at each place that the stairway turns. (It is possible to use "winders" instead, but they aren't generally recommended or allowed by most codes.) See the diagrams above.

Therefore:

Make a two story volume to contain the stairs. It may be straight, L-shaped, U-shaped, or C-shaped. The stair may be 2 feet wide (for a very steep stair) or 5 feet wide for a generous shallow stair. But, in all cases, the entire stairwell must form one complete structural bay, two stories high.