Requirements for Standard Stair Riser Height OSHA 1910.25(c) specifies a maximum riser height of 9.5 inches for regular staircases (24 cm). Stair riser heights must be no more than 7 inches (178 mm) and no less than 4 inches (102 mm) according to IBC 1011.5.2. If the staircase has an odd number of steps, the last riser should be 4 inches high.
The old rule was that risers had to be at least 1 foot (30.5 cm) high, but that's now been changed to allow for shorter risers. In fact, some stair manufacturers advertise their stairs as being suitable for those with limited mobility who may have trouble climbing higher-rise stairs built under the old rules. But regardless of how well you fit into your home, it's important to use caution not to put too much weight on a riser and cause it to collapse.
Stair riser heights affect how many people can climb up or down a staircase at one time. The required clear width between stairs is based on the riser height: 12 inches (305 mm) for risers between 4 and 7 inches (102 and 178 mm) wide; 14 inches (356 mm) for risers between 7 and 10 inches (178 and 250 mm) wide; 16 inches (406 mm) for wider risers.
Stair riser heights must be no more than 7 inches (178 mm) and no less than 4 inches (102 mm). The riser height is determined by measuring vertically between the nosings of neighboring treads. The exact dimensions of the riser don't matter as long as it doesn't interfere with your ability to climb the stairs.
The purpose of the riser is to prevent people from falling through gaps in the floorboards. Without risers, every stair would be equally dangerous, because there would be no way for people to tell if a board was missing or not. By using risers, stairs become safer because they give people something to hold on to while walking up them.
In addition to preventing falls, risers also improve the appearance of the staircase. If you remove all the boards from underneath a staircase, you will see the stringers and beams that make up the support structure of the house. These are usually found near the center of the staircase where they can support the most weight.
The riser is only required on stairs that are less than 18 inches (45 cm) wide. On wider stairs, the risk of someone falling through the floor is so low that there is no need for a riser. You should still use caution when climbing these steps, though. There is nothing to stop someone from stepping out into an unoccupied space below.
The 2018 IBC building code specifies a maximum rise of 7" and a minimum run of 11" for stair rise and run (tread depth). OSHA requires a maximum rise of 9.5" and a minimum run of 9.5" for stair rise and run (tread depth). A single stair flight has an IBC maximum climb of 12'. There are no requirements for handrails on interior stairs.
The standard for stair nosing is 1/4" thick solid wood or metal. The back of each step should be flat and stable. Steps should be wide enough for people to stand on them comfortably, and there should be a 2" space between steps.
Stair stringers are thin boards used as a base for the steps. They should be flat, smooth, and free of cracks or other defects that could cause feet to slip.
The standard for stair landing areas is 4' x 6', but landings can be smaller if there's not enough room behind the walls. Landings must have a continuous surface that is level, smooth, and free of defects such as knots or cracks. The code does not require any specific treatment of landings; builders may choose to paint them or leave them natural.
There are three types of staircases: open, closed-cornered, and half-open. On open staircases, there is no wall at the bottom of the staircase.
The actual climbability will vary depending on how many steps there are in a flight, how wide they are, and whether or not they have a handrail.
The code inspector can measure your stairs to make sure you're complying with the requirements. Stair climbing ability varies from step to step, so an overall assessment of the climbability of your stairs is necessary to determine what type of handrails you need and where they should be placed to provide the most protection for users.
It's important to note that these are only guidelines. If you want your house to be able to be climbed in its entirety, then you should follow federal safety standards as well. The best way to ensure proper safety is through education: learn about fall prevention practices and ask questions if you have them.
Additionally, if you have any concerns about the condition of your stairs, have someone check them out before you put any weight on them. There may be parts of the staircase that aren't safe to walk on if it has been deteriorating for some time without being repaired.