Stair tread depth as for stair treads the depth should not be less than 10 inches however this will require nosing projections.
Stair tread sizes building regs.
If the total rise of the stairs is 2 6 m 8 1 2 feet and the maximum rise permitted by regs is 22 cm 8 21 32 inch divide the total rise of the stairs by the rise permitted by code.
In these cases ensure that the stair width within the entrance storey of a building is 900mm minimum.
Now you need to calculate the number of treads.
The largest nosing projection cannot be more than 3 8 inch greater than the smallest nosing projection.
Building regs k m bs8300 and bs9266 these state that the tread should measure between 50 65mm and the riser 30 55mm.
For dwellings steps may have open risers if treads overlap by a minimum of 16 mm and steps are constructed so that a 100 mm diameter sphere cannot pass through the open risers.
The height and depth of stair treads must be consistent throughout each flight of stairs.
Not of mesh or perforated metal.
Standard risers are around 200mm so aim for this.
The pitch of a private stair flight may be steeper than that of a public flight any other stair in recognition that users as occupants will be more familiar with the stair through.
To avoid having to install nosing the code requires the depth of the tread to be no less than 11 inches.
A tapered tread is a step in which the going reduces from one side to the other.
If the stair is higher than 10m or three storeys the treads must be solid ie.
Nosings must project at least 3 4 inch and no more than 1 1 4 inches beyond the riser below.
Some of the key code regulations for stairs serving habitable rooms are.
A typical rise is 2 600mm which divides easily into 13 200mm risers or steps.
The greatest tread depth within a flight of stairs cannot be more than 3 8 inch larger than the smallest tread depth.
Maximum width of staircase the maximum width of a public staircase is 2000mm measured between inside faces of handrails.
Sans10400 building regulations south africa sans10400 are the building regulations in south africa and both international and national standards are fundamental to successful building and construction projects both big and small.
Nosing that is beveled should not exceed inch or the radius of curvature not more than 9 16 inch.
This ensures there is a large enough band on the nose of the step.
Each flight must not have more than 18 or less than 2 risers.
Treads of stairways that do not have solid risers must overlap the next tread by at least 25 mm see drawing.
To stay within building regulations a domestic staircase needs a rise of between 190mm and 220mm.
