Are you thinking of building a spiral staircase for your home or business? Great! One of the first steps in the process is learning the building codes that apply to your type of building. Keep in mind that your inspector will be watching out for these details and whether you comply or not.
Code requirements for stairs exist for a reason. They are intended to ensure the safety of everyone using the building by setting specific dimensions and standards. Here are the main staircase code regulations set out by the International Building Code (IBC) organization.
Codes for Residential Buildings
The International Residential Code (IRC) regulates the codes specific to staircases in residential buildings. According to the IRC stair codes, your staircase needs to have a minimum stair width of 36 inches. The stair riser should not exceed 7.75 inches, and there could be no more than ⅜ of an inch variation between steps. The standard tread depth code of residential stairs should be at least 10 inches with nosing and at least 11 inches without nosing. The maximum tread depth variation should, again, be less than ⅜ of an inch.
Codes for Commercial Buildings
It is the IBC that sets the code requirements for stairs in commercial buildings. There are small differences between the regulations for residential and commercial premises. For example, the code for stair height is a minimum of 4 and a maximum of 7 inches for the tread. The minimum tread depth is 11 inches. The tolerated difference in depth and height is just like for residential buildings — ⅜ of an inch. Another difference for commercial buildings is that stair tread nosing is not required (as long as you have a minimum tread depth of 11 inches).
Spiral Staircase Regulations
In addition to the staircase code requirements above, there are also some specific dimensions for spiral staircases. According to the International Code Council (ICC), your spiral staircase should have a minimum 6 ¾-inch tread depth at a point that is 12 inches from the narrow edge. The risers should provide headroom of at least 78 inches, but they should not exceed 9 ½ inches. You also need to have a minimum of 26 inches clear width below and at the handrail.
Now that you know the building code requirements for stairs, it is time to go ahead of choosing the right spiral staircase. If you say yes to quality, German-made steel stairs, then you are in the right place!