But we recommend that stairs should be at least 48 inches wide so they don t feel cramped.
What is a standard stair tread size.
Regulated by building codes stair details specify the sizes of risers and treads stair widths the placement of handrails and guardrails and construction methods for fabricating stairs.
For recommendations on rise run combos see the tip below.
Stair details refer to the standard requirements for each of the various components of a flight of stairs.
The minimum tread size is commonly stated as 9 inches for residential construction.
Standard code requires that each stair tread fall between 9 inches and 11 inches 22 9 cm and 27 9 cm to allow people to safely ascend and descend stairs.
Nine inch stair treads are the most common lengths.
The maximum allowable stair rise is 7 3 4 inches and the minimum stair rise is 4 inches.
Here is a drawing detailing our standard stair tread and riser dimensions.
Most stair treads are not made to wrap around the lip of the stair.
Increasing the length of the run by the smallest unit of measurement increases cost and the length of a staircase.
The stair tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at right angle to the tread s leading edge.
A tread thickness b bull nose height 1 1 16 c bull nose depth 1 d internal length 36 42 or 48 e return length 13 f tread width 11 g return extension 1 h return width 1 i external length 38 5 44 5 or 50 5.
At the same time staircase code measurements do allow for some flexibility since most measurements are accompanied by minimums or maximums.
The stair treads should be at least 36 inches wide.
Staircase code states that stairs must be 3 feet wide or wider.
Because they only sit on the top of the stair the length of the tread is limited to the size of the average step.
As long as the 3 foot width standard is met you can expand the stairs width as far as you wish.
Standard stair tread dimensions.
Most stair treads measure between 8 and 10 inches long with longer treads being used on larger staircases.
Harvard university lists typical tread sizes between 8 and 11 1 2 inches.
Stair tread depths shall be 11 inches 279 mm minimum.