Spiral Staircase Regulations British Standard 5395 part 2

The document governing spiral staircase building standards in the UK is British Standard 5395 part 2.

The staircase in your building project will need to conform to Building Regulations. Building regulations relate to the shape, depth, height, and level of your staircase as well as the pitch, the clearance above it and the width of the landings.

Details of permitted handrails and balustrades as well as their related heights and the distance between the balusters are also covered. The building regulations issues can be explored on the excellent government website www.planningportal.gov.uk. You may also Click here to download ‘Approved Document K – Protection from falling, collision and impact’ in Pdf. format direct from the building regulations website.
PLEASE NOTE: THERE IS A NEW VERSION OF APPROVED DOCUMENT K This is in effect from 6th April 2013. The above link takes you to the new version of the document

These building regulations will dictate to a greater or lesser extent what you can achieve with your staircase design.

The main points to note regarding building regulations for a staircase from this document are:

  • The minimum tread size (the horizontal part of each stair) is 220mm from the nosing to the nosing of the next tread and the riser (the height of each step) must be between 190mm and 220mm.
  • There are no recommendations for minimum staircase widths, the width of a standard flight of a staircase is 860mm and anything less than 600mm is impractical. The gradient (pitch cannot be greater than 42 degrees).
  • A staircase with open risers likely to be used by children under five should be built so that a 100mm sphere cannot pass through the open risers. The same regulation applies to the balusters – described in the regulations as the ‘guarding’.
  • Staircase Landings should generally be provided at the top of each flight.

Clear headroom of 2000mm should be provided over the whole width of your staircase but this can be reduced to 1900mm in some situations for loft conversions.

This document is summarised in the table below with categories given for each spiral application and the relevant maximum riser heights and minimum widths. The table below is for guidance only – please check with your local planning authority for confirmation.

EXTRACT FROM BS5395 part 2 Minimum Clear Tread Width Riser Height Minimum InnerGoing Minimum CentreGoing    Maximum Outer Going
Category A – Small Private StairSecondary domestic stair intended to be used by a limited number of people who are generally familiar with the stair 600mm – typical minimum diameter 1500mm 170-220mm 120mm 145mm 350mm
Category B – Main Private StairSimilar to category A but also providing the main access to the upper floor of a private dwelling 800mm – typical minimum diameter 1800mmN.B – 900mm in Scotland 170-220mm 120mm 190mm 350mm
Category C – Small Semi Public StairSmall commercial stair providing access      for up to 50 people.  Intended to be used by those generally familiar with the stair.

Centre column handrail required

 800mm – typical minimum diameter 2000mm 170-220mm 150mm 230mm 350mm
Category D – Semi Public StairIntended to be used by large numbers of people, some of whom may be unfamiliar with the stair.  Generally providing access for more than 50 people.

Centre column handrail required

 900mm – typical minimum diameter 2300mm 150-190mm 150mm 250mm 450mm
Category E – Public StairLarge commercial stair designed to be used by many people at one time e.g. place of public assembly.

Centre column handrail required

 1000mm – typical minimum diameter 2500mm 150-190mm 150mm 250mm 450mm