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).
Once the concrete stair treads are installed, people have a safe and permanent egress from inside and outside the structure. The standard size of a concrete stair tread is 24 or 48 inches by 14 inches with thicknesses dependent on the tread profile. These edge profiles include bullnose, wedge, square, and dropped. The bullnose profile has a thickness of two inches.