Stairs - UK Building Regulations

UK Building Regulations

(overview of Approved document K - Stairs Ramps and Guards)

Approved document K categorises stairs as ‘Private’, ‘Institutional or assembly’ and ‘other’

When considering stairs for private dwellings

Building regulations are required for stairs used where the difference of level is greater than 600 mm (23.6 in)

Steepness of stairs – Rise and Going - Any rise between 155 and 220 mm (6.1 and 8.7 in) used with any going (tread) between 245 and 260 mm (9.6 and 10.2 in) or any rise between 165 and 200 mm (6.5 and 7.9 in) used with any going between 223 and 300 mm (8.8 and 11.8 in)

Maximum Rise 220 mm (8.7 in) and Minimum Going 220 mm (8.7 in) remembering that the maximum pitch of private stairs is 42⁰. The normal relationship between dimensions of the rise and going is that twice the rise plus the going (2R + G) should be between 550 and 700 mm (21.7 and 27.6 in)

Construction of steps - Steps should have level treads, they may have open risers but if so treads should overlap at least 16 mm (0.6 in). Domestic private stairs are likely to be used by children under 5 years old so they should be constructed so that a 100 mm (3.9 in) diameter sphere cannot pass though the opening in the risers.

Headroom - A headroom of 2 m (78.7 in) is adequate. Special considerations can be made for loft conversions see paragraph 1.10 of the approved document for clarification on the 1.9 tapering to 1.8 m (70.9 in)

Width of flights - No recommendations are given for stair widths in the Approved document K for stairs but designer’s attention is drawn to approved document B: fire safety.

Length of flights - The approved document refers to 16 risers (steps) for stairs in shops or assembly building. There is no requirement for private stairs. In practice there will be less than 16 steps as 16 mm × 220 mm (0.6 in × 8.7 in) gives over 3.5 m (137.8 in) total rise which is way above that in a domestic situation.

Landings - Level, unobstructed landings should be provided at the top and bottom of every flight. The width and length being at least that of the width of the stairs and can include part of the floor. A door may swing across the landing at the bottom of the flight but must leave a clear space of at least 400 mm (15.7 in) across the whole landing

Tapered steps - There are special rules for stairs with tapered steps as shown in the image Example of Winder Stairs above

Alternate tread stairs can be provide in space saving situations

Guarding - Flights and landings must be guarded at the sides where the drop is more than 600 mm (23.6 in). As domestic private stairs are likely to be used by children under 5 the guarding must be constructed so that a 100 mm (3.9 in) diameter sphere cannot pass through any opening or constructed so that children will not be able to climb the guarding. The height for internal private stairs should be at least 900 mm (35.4 in) and be able to withstand a horizontal force of 0.36 kN/m (2.1 lbf/in).