How deep should a stair tread be? A stair tread should be a minimum of 11″ deep for stairs used as a means of egress under the 2018 IBC building code. A stair tread should be a minimum 9.5″ deep for stairs used as equipment access under the OSHA standards for stairways.
For both the IBC and the ADA, the 7/11 rule applies: riser height is a maximum of 7 inches and minimum of 4 inches and tread depth is a minimum of 11 inches. When you're walking either up or down stairs, you don't want to have to think about each step, you want to walk with a cadence.
The general rule in the United States is a 7" rise and 11" tread depth.
The "27 Rule" for stairs is a helpful guideline for determining comfortable stair dimensions. According to this rule, the sum of the riser height and the tread depth should equal 27 inches. For example, if the riser height is 7 inches, the tread depth should be 10 inches.
The sum of one rise and one tread should be 17-18 inches. If the sum is greater than 18 3/4 inches, there's a mistake. Correct your measurements. After calculating the stair stringers' rise and run, make a sketch of the staircase and label the measurements as a visual aid.
Standard Stair Tread Depth Requirements
Under OSHA, a standard stair means a fixed or permanently installed stairway that is not an alternating tread stair, ship stair, or spiral stair. OSHA 1910.25(c)(3) requires standard stairs to have a minimum tread depth of 9.5 inches (24 cm).
Ratio between height (rise r) to width (tread t) of the step. This follows the golden rule which is: 2 x r + t = 63 cm. i.e.: 2 times the rise plus the tread equals 63 cm with a maximum variation of ± 1 cm.
The old-fashioned rule was that a lady would precede the gentleman up the stairs in case she were to fall -- ensuring that he could then assist her.
Stringer framing should always be cut from a 2x12, by the way. I have seen them cut from 2x10 and even 2x8 before for some ridiculous reason. DON'T DO IT!
An 8-inch step is generally too high for most stairs. The best riser height is between 7 and 7.5 inches. Steps that are too high can be hard to climb and might cause tripping, especially for kids and older adults.
According to OSHA, a standard stair refers to any fixed or permanent stairway aside from alternating tread stairs, ship stairs, or spiral stairs. Standard stairs must, at minimum, maintain a tread depth of 9.5 inches, or 24 cm, under OSHA 1910.25(c)(3). IBC 1011.5.
Exterior stair tread code
Exterior stair treads must comply with all the general stair tread requirements found in IBC section 1011.5 Stair treads and risers. The minimum tread depth shall be 11 inches.
Williams defines step length as “the distance between successive footstrikes of different feet” and stride length as “the distance from one foot contact to the next contact of the same foot.” G. A. Westerfield, writing about race walking, defines a step as the distance “from toe off to heel strike of the same foot” and ...
Research shows that a rise plus run (r+R) of 46cm is a comfortable stride for most people. Less than 43cm will require strides that will be too short for most people, while more than 48cm will likely be too much of a stretch.
The tread depth code for residential stairs should be no less than 10 inches with nosing, no less than 11 inches without nosing, and maximum tread depth variation should also be less than 3/8 of an inch.
The following is a rule-of-thumb formula for interior stairs, as specified in the Architectural Graphic Standards. Riser + Tread = 17.5 inches (445mm): 7.5 inches (191mm) for the riser height; 10 inches (254mm) for the tread depth. Riser * Tread = 75 inches (1905mm).
The "27 Rule" is a handy way to figure out how deep and tall each step should be. According to this rule, if you add the height of the riser (the vertical part) and the depth of the tread (the horizontal part), it should equal 27 inches.
Stability is crucial when making deck stairs, so you must attach supports. From the back, screw a piece of 2x6 horizontally along the width of all stringers. Then, take two more pieces of 2x6 and fix them vertically, attaching them to the back of the deck rim and the first piece of 2x6.
The International Residential Code (IRC) specifies that the minimum overhang for a stair tread should be 3/4 inch, while the maximum overhang should be 1 1/4 inches. For optimal comfort and safety, it is recommended that the overhang distance be between 1 and 1 1/4 inches.
To summarize: The rise plus the run (r+R) should be within an inch of 18”. Twice the rise plus the run (2r+R) should be within an inch of 25”. Break those rules at your own risk.
If the revolving door is automatic, the rules are the same as regular doors: ladies go first in social settings and higher-ranking individuals go first in business settings. Opening doors is an act of kindness that can be shown to anyone—regardless of gender, rank, or age.
Meaning. The analogy of the missing stair makes it clear that the problem is the predator (the missing stair) and that the solution is stopping the predatory behavior (fixing the stair).
Ergonomic Efficiency: At 37 degrees, the ratio of the tread (the horizontal part where you step) to the riser (the vertical part between treads) is optimized for average human stride lengths. This angle ensures that the stairs are not too steep or too shallow, providing a natural and comfortable ascent and descent.
Crossing on the stairs invokes bad luck
Many believe that crossing someone on the stairs will bring you bad luck. The origin is down to suggestions rather than anything else; some say it was before the stair bannister was invented, and crossing on the stairs could lead to one person falling off.