Building codes limit variation to 3 8 10 mm the underside of risers should be sloped or have a 60 angle minimum between nosings and the horizontal surface open risers are not allowed under ada guidelines.
Stair tread measurements.
While a tape measure isn t a tool that is specifically for stair measuring it is one of the most common.
Standard stair treads all wood species excluding the following.
Stair tread depths shall be 11 inches 279 mm minimum.
Bamboo acacia kempas and strand eucalyptus only available in 48 and no custom dimensions standard treads provide a perfect solution for boxed staircases that are contained by walls on both sides.
Here is a drawing detailing our standard stair tread and riser dimensions.
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.
Building codes generally suggest that the minimum length of a tread be 10 inches 25 4 cm.
The rise or height of a step is measured from the top of one tread to the top of the next tread.
Riser and tread dimensions should be continuously uniform for safety.
It is not the physical height of the riser because this excludes the thickness of the tread.
Standard stair tread dimensions.
The stair tread depth red arrow is measured from the forward edge of the step nose or edge of the step above out to the leading edge of the step being measured.