Staircases

6.6
See Also:
BS 5395

6.6.7Design of steps

Steps shall be constructed to allow the safe use of the staircase. Issues to be taken into account include:

  1. pitch
  2. steps
  3. tapered treads and winders.

Pitch

The maximum angle of pitch of a stairway should not exceed:

  • 42° for private stairs
  • 38° for common or access stairs.

The dimensions for maximum rise and minimum going should be as in Table 2.

Table 2: Maximum rise and going

Type of stairsMaximum rise (mm)Minimum going (mm)
Private stairs220220
Common stairs (not Scotland)190250
Access stairs (Scotland)190250

Staircases should be accurately located and fixed with the string at the correct angle to ensure all treads are level.
Stairs should be dimensioned so that the rise (R) and the going (G) is between 550mm and 700mm when using the equation: 2R + G (see Chart 1).

Chart 1: Dimensions for rise and going

Steps

In each flight:

  • the tread should be level
  • the rise and going should be consistent
  • the thicknesses of screeds and floor finishes should be taken into account to ensure that all risers are equal
  • the treads should overlap by a minimum of 16mm, where the riser is open.

Where stairs are open to the weather, or may otherwise become wet, one of the following should be specified:

  • A non-slip finish.
  • A non-slip insert to each tread.

Tapered treads and winders

The rise of tapered treads should be the same as that of adjacent parallel treads. The going should be:

  • uniform and no less than the going of the associated straight flight, measured from the centre line of the straight flight
  • a minimum of 50mm at the narrowest point.