Spiral Staircase Building Regulations

UK staircase regulations

There are three main building regulations that relate to staircases, generally referred to as Part K, M & B.

Approved Document K
Protection from falling collision and impact. (Section 1: Stairs)

Approved Document B
Fire Safety (means of escape)

Approved Document M
Access to and use of buildings (Disabled Access)

What are the Building Regulations for Spiral Staircases in the UK?

Spiral and helical stairs regulations

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

In Approved Document K 1.28 it says:

“Design spiral and helical stairs in accordance with BS 5395-2”

All the spiral and helical staircases that we manufacture at Spiral UK are compliant with British Standards Document BS 5395 Part II.

Spiral staircase or helical stairs regulations for residential properties

The staircase categories relating to residential spiral or helical staircases tend to be A small private stair or B private stair. Part B & M of the Building Regulations for staircases don’t tend to apply to residential properties.

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 the 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

Spiral staircase regulations for commercial and public use

Category C small semi-public, D semi-public or E public stairs tend to be for staircase projects in commercial and public spaces.

It is important to note that where there is a contradiction between BS 5395 Part II and Part B and M of the Building Regulations, Part B and M take precedence.

Category C – Small Semi-Public stair

This type of stair is intended for use by a limited number of people some of whom maybe unfamiliar with it. Typical examples are stairs in offices, a factory or for a stair serving more than one 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: 230mm

Category D – Semi-Public stair

This category of stair is intended for use by larger numbers of people some of whom maybe unfamiliar with it. It suits larger floor areas in a factory, shop or office or can be a common stair serving more than one dwelling.

• Minimum and maximum rise per tread: 150-190mm
• Minimum clear width between core pole & handrails: 900mm (900 in Scotland)
• Minimum going from the centre of the tread: 250mm

Category E – Public stair

Public stairs are for use by large numbers of people at one time and used in places of public assembly.

• Minimum and maximum rise per tread: 150-190mm
• Minimum clear width between core pole & handrails: 1000mm (900 in Scotland)
• Minimum going from the centre of the tread: 250mm

General considerations

Risers
The maximum number of risers in a single flight should be 16 except where this is not practicable then the number of risers can be increased to 22.

Headroom
Normally the clear headroom** should be 2000mm it may be reduced to 1900mm where this is not practicable

Balustrade
In areas used by children the widest gap between balusters should not allow a sphere of 100mm to pass through. We call this the 100mm rule and apply it to most of our helical and spiral staircases.

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

If you would like to discuss your staircase design ideas with us please get in touch we would be happy to help.

*clear width is the unobstructed walking area throughout the spiral stair’s rise

**clear headroom is the distance measured vertically from the pitch line of the stair or from a floor or landing to any obstruction overhead