Rise

The angle of the rise in a stairway, also referred to as the incline, must not be less than 30 degrees and not more than 50 degrees. The majority of people prefer a rise between 30 degrees and 35 degrees. Different degrees in the rise require different riser heights (step height) and different tread runs (step depth). In general, as you reduce the riser height, you want to increase the tread run.

Different types of stairs have different recommendations for riser height and tread run.

When step risers are less than four inches, people tend to trip on the mini step. When the riser is too tall, more than 8 inches, it takes greater effort to climb the stairs, which increases the falling or tripping hazard. A typical rule of thumb is that the rise plus the run should equal between 17 inches and 17 and one-half inches.

Most importantly, the rise must be consistent throughout the stairway. Regulations state that the variation in riser height and tread run must not exceed .25 inch.

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