While not new, since the concept was already described by Christopher Alexander in its architectural theories, it only gathered some traction in programming due to the publication of Design Patterns: Elements of Reusable Object-Oriented Software book in October 1994 by Erich Gamma, Richard Helm, Ralph Johnson and John Vlissides, known as the Gang of Four (GoF), that identifies and describes 23 classic software design patterns.
Use a calculator to calculate the stair riser length or the number of steps you'll need. Divide the height from the first floor to the top of the second floor by a predetermined height of your choice for the riser. The typical height of a riser is 6 or 7 inches (15 to 17.5 cm).
Establish the run of each step to get the total run of the staircase. The run of each step should be no less than 9 inches (23 cm) and realistically at least 10 inches (25 cm). Multiply the total number of steps by the run of each step: 13 total steps x 10 inches = 130 inches (330 cm) total run.The total run is the horizontal distance the stairs will travel from beginning to end. The rule of thumb for treads and risers is that the sum of each should equal between 16 and 18 inches (40 and 45 cm). 2  So, if your riser is 7 inches (17.8 cm) tall, your tread should be anywhere from 9 to 11 inches (23 to 28 cm) long.