Guidance on building regulations for residential staircases

UK staircase regulations
There are three main building regulations that relate to staircases generally Part K, M & B. In addition to this more specifically spiral and helical staircases fall under BS 5395 Part II.

What regulations cover spiral and helical stairs?

Part K of the Building Regulations provides the guidelines for ensuring occupants or visitors to a house are protected against falling, collision or impact.

The rules within Part K don’t apply to spiral or helical staircase designs but instead state that for a spiral staircase design, the British Standards Document BS 5395 Part II applies.

Spiral UK have developed guidance on the standards for spiral and helical staircases in the form of British Standard specification sheets for the different categories of spiral and helical stairs. You can download them at technical information

Category A – small private stair

This type of spiral or helical stairs is intended for use by a limited number of people who are generally familiar with staircase. For example, an internal stair in a dwelling serving one room not being a living room or a kitchen, an access stair to an office not used by the public, or spiral fire escape stairs for a small number of people.

Minimum and maximum rise per tread: 170-220mm

Minimum clear width between core pole & handrails: 600mm

Minimum going from the centre of the tread: 145mm

Category B – private stair

In addition to a category A stair, this private stair can also provide the main access to the upper floor of a private dwelling.

Minimum and maximum rise per tread: 170-220mm

Minimum clear width between core pole & handrails: 800mm (900 in Scotland)

Minimum going from the centre of the tread: 190mm

Approved Document K requires that if a staircase design uses consecutive tapered treads they should all have a consistent going (the horizontal distance between the edge of one tread and the next).

If a stair includes a mixture of straight and tapered treads, the going of the tapered treads should not be less than the going of the straight treads.

What is the minimum width of a flight of stairs?

For accessibility you should try to avoid a stepped level change on the entrance storey of a house. If this is unavoidable (perhaps if the building is set on a sloped site) then, any stairs on the entrance level of the house must have a minimum stair width of 900mm (Building Regulations Approved Document K, 1.16).

What is the maximum length of a flight of stairs?

If a staircase is made up of more than 36 risers in one consecutive line, then you must include at least one change of direction in the staircase. You can do this by including a landing to separate the flight into two or more sections. (See 1.17 of the regulations Approved Document K).

What are the landing requirements for stairs

At the top of each flight of stairs you must have a landing. A landing could be part of the upper floor of the house or part of the staircase structure. The area should be kept clear of permanent obstructions. You can have cupboard doors that open onto the landing, but these should be kept closed/locked under normal conditions and when open should allow at least 400mm of space on the landing between the doors and the edge.

All landings should be completely level.

The landing must be as wide and long as the smallest width of the flight.

For instance, if the stair flight is 900mm wide then the landing must be at least 900mm x 900mm.

Note: if the staircase also forms part of the escape route from the house you will also need to adhere to the requirements in Approved Document B: Volume 1 – Dwellinghouses.

Approved Document B

This area of the building regulations covers means of escape. It looks at fire safety and ensuring occupants have an effective means of escape from all rooms in a building in the event of a fire. In some cases, the staircase may be the only effective means of escape.