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.

What is a standard stair tread size.

Staircase code states that stairs must be 3 feet wide or wider. Most stair treads measure between 8 and 10 inches long with longer treads being used on larger staircases. Here is a drawing detailing our standard stair tread and riser dimensions. Harvard university lists typical tread sizes between 8 and 11 1 2 inches.

The maximum allowable stair rise is 7 3 4 inches and the minimum stair rise is 4 inches. 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. Unit run is carefully considered based on both safety and cost. Because they only sit on the top of the stair the length of the tread is limited to the size of the average step.

Increasing the length of the run by the smallest unit of measurement increases cost and the length of a staircase. Standard stair tread dimensions. As long as the 3 foot width standard is met you can expand the stairs width as far as you wish. Nine inch stair treads are the most common lengths.

A prime example is the standard stair width. For recommendations on rise run combos see the tip below. The minimum tread size is commonly stated as 9 inches for residential construction. Stair details refer to the standard requirements for each of the various components of a flight of stairs.

But we recommend that stairs should be at least 48 inches wide so they don t feel cramped. These dimensions may be useful when laying out a staircase or if you have general questions about the size and shape of a traditional tread or a retro tread. 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. At the same time staircase code measurements do allow for some flexibility since most measurements are accompanied by minimums or maximums.

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.