NHBC Standards 2006

6.6 Staircases

SCOPE

This Chapter gives guidance on meeting the Technical Requirements and recommendations for staircases.

DESIGN STANDARDS

6.6 - D1Design standards
6.6 - D2Statutory requirements
6.6 - D3Safe transmission of loads
6.6 - D4Staircase width and headroom
6.6 - D5Design of steps
6.6 - D6Landings
6.6 - D7Handrails
6.6 - D8Guarding
6.6 - D9Fire Precautions
6.6 - D10Lighting
6.6 - D11-D12Provision of information

6.6 - D1
Design shall meet the Technical Requirements
 

Design that follows the guidance below will be acceptable for staircases.

STATUTORY REQUIREMENTS

6.6 - D2
Design shall comply with all relevant statutory requirements
 

Design should be in accordance with relevant Building Regulations and other statutory requirements.

SAFE TRANSMISSION OF LOADS

6.6 - D3
Design shall ensure that loads are properly supported and transmitted to the supporting structure without undue movement, deflection or deformation
 

Generally, all stairs and staircases should comply with BS 5395 : Parts 1 and 2.

Items to be taken into account include:

(a)
timber staircase construction
 

Timber domestic staircases with straight flights and quarter- or half-landings should comply with BS 585. Particular attention should be paid to the performance requirements for strength, deflection and vibration under load, given in BS 585 : Part 2.

The method of fixing flights to the surrounding structure should be specified.

(b)
concrete staircase construction
 

Reinforced concrete staircases should be designed to BS 8110 and comply with Chapter 2.1 'Concrete and its reinforcement' (each section) and, where appropriate, designed by an Engineer in accordance with Technical Requirement R5.

(c)
steel staircase construction
 

Steel staircases should be designed to BS 5950.

(d)
proprietary staircase construction
 

Proprietary staircases should:

(e)
differential movement
 

When considering differential movement in relation to setting out, levels and finishes, allowances should be made for:

  • casting tolerances
  • deflection under load
  • foundation settlement
  • creep and shrinkage
  • storey height.

STAIRCASE WIDTH AND HEADROOM

6.6 - D4
Staircase design shall ensure adequate provision for:
 

(a) headroom

The minimum headroom above stairs should be measured vertically from the pitch line. The clear headroom (h) over the entire length and width of a stairway, including landings, should be 2.0m.

Staircase headroom

(b) minimum unobstructed width

No recommendations are given for minimum widths in England, Wales and the Isle of Man. Where staircases form part of means of escape, reference should be made to the relevant Building Regulations.

Dimensions for stair widths in Scotland and Northern Ireland should be in accordance with relevant Statutory Requirements.

DESIGN OF STEPS

6.6 - D5
The design of steps shall allow safe use of the staircase
 

Items to be taken into account include:

(a) pitch

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

  • 42° for private stairs
  • 38° for common or access stairs.
Angle of pitch of a stairway

The dimensions for maximum rise and minimum going should be:

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


The dimensions of the rise (R) and the going (G) should usually be related so that 2R+G is between 550mm and 700mm.

A design aid giving the relationship between rise and going is given in Appendix 6.6-A.

Further information on staircase design may be found in BS 5395.

(b) consistent rise and going

In each flight of stairs all the steps should have the same rise and going.

The thicknesses of screeds and floor finishes should be taken into account.

Consistant rise and going

(c) 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 not less than the going of the associated straight flight. The going should be measured from the centre line of the straight flight (as shown below).

Tapered treads and winders


Minimum going (g) [mm]
England and Wales 50
Scotland 50
Northern Ireland 50
Isle of Man50

(d) safe foothold

All steps should have level treads.

Stairs with open risers should have treads that overlap 16mm minimum.

Safe foothold

Where stairs are open to the weather or may otherwise become wet, a non-slip finish or an insert to each tread should be specified.

LANDINGS

6.6 - D6
Landings shall be designed to allow safe use of the staircase
 

Landings should be provided at the top and bottom of every flight. The width and depth of landings should be at least the same as the width of the stair.

Landings should be properly framed to provide full support and secure fixings for flights, nosings, newels, etc.

Where pivot windows are being used, they should not obstruct the landing area or stair flight when in the open position.

Generally, door swings should not obstruct landings. However, a door may open across the bottom landing of a flight of private stairs if the swing is at least 400mm from the first tread and the dwelling is not over two storeys high.

Landings designed for safe use of staircase

HANDRAILS

6.6 - D7
Handrails shall be designed to provide a safe handhold
 

A handrail is required to all flights of stairs that rise over 600mm.

Where winders are used, Building Regulations (Northern Ireland) require a handrail to be fitted on the side where tapered treads have the greater going.

Handrails should be at a height between 900mm (840mm in Scotland) and 1000mm.

Design should ensure:

  • a firm handhold
  • that trapping or injuring the hand is prevented
  • a minimum 25mm clearance at the back of the handrail
  • secure fixing
  • that handrail ends do not project to catch clothing, etc.
Handrails

GUARDING

6.6 - D8
Guarding shall be designed to prevent accidents by falling
 

Items to be taken into account include:

(a) resistance to loads

Guarding should be:

  • capable of resisting a horizontal force of 0.36kN/m at its minimum required height
  • a solid wall or balustrading.

Where guardrails or balustrades are long, the newel posts may not be sufficient to transfer horizontal forces to the structure and intermediate posts may be needed.

The method of fixing newels should be specified (eg through-bolted to joists).

Any glazing in the guarding should be toughened or laminated glass, or glass blocks. Wired glass is not regarded as safe for this purpose and should not be used.

(b) dimensional requirements

Guarding should be provided along the full length of the open sides of all stairs and landings when the drop is more than 600mm at any point. To comply with relevant Building Regulations, guarding may be required where a stair abuts an opening window.

Guarding is not needed when the rise is less than 600mm and when the stair or landing is not a means of escape.

Balustrading should be designed so that it is not easily climbed by children.

No opening in the balustrade should be large enough for a 100mm diameter sphere to pass through.

Type of stairsMinimum guarding height [mm]

flightslandings
Private stairs (England,
Wales, Northern Ireland
and the Isle of Man)
900 900
Private stairs (Scotland)840 900
Common stairs9001100

FIRE PRECAUTIONS

6.6 - D9
Staircases shall provide the necessary means of escape in case of fire
 

Timber staircases are acceptable within a single family dwelling where there are no more than four storeys, excluding the basement.

Houses of three or more storeys and flats in buildings of three or more storeys should comply with the relevant Building Regulations.

Ventilation of staircases serving flats in buildings of three or more storeys should comply with BS 5588.

LIGHTING

6.6 - D10
Lighting shall be provided to ensure safe use of the staircase
 

Artificial light sources should be provided to all staircases and landings. Within dwellings, lighting to stairs should be controlled by two way switching.

Where the Public Lighting Authority specify and maintain control of entrance lighting, their requirements should be met. Otherwise, landings and staircases in common areas to dwellings should be provided with adequate artificial lighting. Manual two way switching, controlled by people using these areas is acceptable. Automatic light sensitive controls may be used, provided lights can also be switched two way manually.

Reference should be made to Chapter 8.1 'Internal services' (Design) for further details on lighting.

Where staircases are lit by glazing, any glass below the minimum height of guarding (see Table to Clause D8(b)) should be:

  • protected by a balustrade or railing, or
  • glass (toughened or laminated), or
  • constructed of glass blocks.

PROVISION OF INFORMATION

6.6 - D11
Designs and specifications shall be produced in a clearly understandable format and include all relevant information
 

Usually, staircase drawings and specifications should show:

  • layout of stairs
  • dimensions covering width, rise and going, handrail height, etc
  • fixings of stairs, treads, risers, strings, balustrades, newel posts and handrails, as appropriate
  • the length of time before formwork can be removed from in-situ concrete stairs
  • whether precast concrete or steel staircases can be used immediately after erection or whether time should be allowed to cure grouted connections.
6.6 - D12
All relevant information shall be distributed to appropriate personnel
 

Ensure that design and specification information is issued to site supervisors and relevant specialist subcontractors and/or suppliers.