The height and depth of stair treads must be consistent throughout each flight of stairs.
Stair tread sizes building regs.
In these cases ensure that the stair width within the entrance storey of a building is 900mm minimum.
Building regs k m bs8300 and bs9266 these state that the tread should measure between 50 65mm and the riser 30 55mm.
This ensures there is a large enough band on the nose of the step.
Now you need to calculate the number of treads.
Stair tread depth as for stair treads the depth should not be less than 10 inches however this will require nosing projections.
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.
260 22 12 steps required to go from the floor to the top of the stairs.
To avoid having to install nosing the code requires the depth of the tread to be no less than 11 inches.
The largest nosing projection cannot be more than 3 8 inch greater than the smallest nosing projection.
A typical rise is 2 600mm which divides easily into 13 200mm risers or steps.
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.
Some of the key code regulations for stairs serving habitable rooms are.
Each flight must not have more than 18 or less than 2 risers.
Maximum width of staircase the maximum width of a public staircase is 2000mm measured between inside faces of handrails.
Nosings must project at least 3 4 inch and no more than 1 1 4 inches beyond the riser below.
To stay within building regulations a domestic staircase needs a rise of between 190mm and 220mm.
The greatest tread depth within a flight of stairs cannot be more than 3 8 inch larger than the smallest tread depth.
A tapered tread is a step in which the going reduces from one side to the other.
Standard risers are around 200mm so aim for this.
Actually there is a small variance between the documents but the consensus is now that the dimensions as shown meet the requirements.
The geometry of a stair flight can have a significant effect on the ability of people to use a stair safely and conveniently and limits should be placed on the rise and going of a stair and steepness of pitch.
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.
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.
Treads of stairways that do not have solid risers must overlap the next tread by at least 25 mm see drawing.
