Not of mesh or perforated metal.
Stair tread sizes building regs.
Stair tread depth as for stair treads the depth should not be less than 10 inches however this will require nosing projections.
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.
Each flight must not have more than 18 or less than 2 risers.
Some of the key code regulations for stairs serving habitable rooms are.
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.
In these cases ensure that the stair width within the entrance storey of a building is 900mm minimum.
Nosing that is beveled should not exceed inch or the radius of curvature not more than 9 16 inch.
Maximum width of staircase the maximum width of a public staircase is 2000mm measured between inside faces of handrails.
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.
Building regs k m bs8300 and bs9266 these state that the tread should measure between 50 65mm and the riser 30 55mm.
Nosings must project at least 3 4 inch and no more than 1 1 4 inches beyond the riser below.
A tapered tread is a step in which the going reduces from one side to the other.
The height and depth of stair treads must be consistent throughout each flight of stairs.
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.
To stay within building regulations a domestic staircase needs a rise of between 190mm and 220mm.
Treads of stairways that do not have solid risers must overlap the next tread by at least 25 mm see drawing.
Standard risers are around 200mm so aim for this.
Now you need to calculate the number of treads.
If the stair is higher than 10m or three storeys the treads must be solid ie.
To avoid having to install nosing the code requires the depth of the tread to be no less than 11 inches.
This ensures there is a large enough band on the nose of the step.
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.
