Stairs

  • Description

A large number of questions have been asked about domestic staircases. Here are the general requirements for stairs Domestic Stairs Design Requirements:

Width of stair flights and landings

The clear, or effective, width of a stair should allow users to move up and down unhindered and, on stairs giving access to a dwelling or domestic building, permit people to pass on a flight.

The effective width should be measured between handrails or, where there is no handrail present, between any walls or protective barriers. It should be clear of obstructions, as described in the diagram to clause 4.3.1. The effective width of a stair should be in accordance with the recommendations of the following table:

Effective widths of flights and landings

Private Stair Any other stair
900 mm [1], such as from one storey to another or connecting levels within a storey; or
600 mm where serving only sanitary accommodation and/or one room, other than accessible sanitary accommodation , a kitchen or an enhanced apartment.
1.0 m generally, such as to an external flight to a domestic building or a common access within a building containing flats or maisonettes ; or
900 mm to an external flight serving a single dwelling, to which the public have access.
Notes:
1. The effective width of a private stair may be 800 mm where a continuous handrail is fitted to both sides of a flight. The projection of any stringer or newel post into this width should be not more than 30 mm.
 

Stair Lifts

A stair lift may be fitted to a private stair and may project into the effective width of the stair. However, in such cases, at least 1 handrail should be present and, when not in use, the installation should:
a. permit safe passage on the stair flight and any landing; and
b. not obstruct the normal use of any door, doorway or circulation space.

Number of rises in a flight

The act of climbing stairs can be tiring to many people. Whilst landings can provide a safe resting point, the flight itself is not intended to do so. The maximum number of rises between landings should therefore be limited.

Generally, a flight should have not more than 16 rises. Below a minimum number of steps, it becomes difficult to signal a change of level, which can contribute significantly to a trip hazard. Generally, a flight should have at least 3 rises. However, people tend to take greater care at certain locations, such as at an external door, and a single step or 2 steps may be appropriate under certain circumstances.

There may be less than 3 rises:
a. other than at an accessible entrance, between an external door of a building and the ground or a balcony, conservatory , porch or private garage; or
b. wholly within an apartment other than where affecting provisions within an enhanced apartment or
c. wholly within sanitary accommodation , other than accessible sanitary accommodation or
d. between a landing and an adjoining level where the route of travel from the adjoining level to the next flight changes direction through 90º (i.e. on a quarter landing as the first step).

Risers and treads

All stairs providing access to and within buildings should be designed to be accessible by most persons with reduced mobility. Open risers on a flight can be a hazard. When ascending a stair, people may be at risk of trapping the toes of shoes beneath projecting nosings, and of tripping as a result. In addition, many may feel a sense of insecurity when looking through spaces present between treads. A stair should have contrasting nosings to assist in identifying the position of treads and risers should be profiled to minimise tripping as shown below. Open rises should not be used unless a stair is intended for descent only, such as in a dedicated escape stair on an escape route./p> However, a private stair may be constructed with open risers and without contrasting nosings as occupants will be more familiar with the stair through frequent use.

Small children can climb or fall through gaps in stair treads and the size of such gaps should be limited to prevent this. In a flight with open rises, the treads should overlap by at least 15 mm. Any opening between adjacent treads in a flight should be small enough to prevent the passage of a 100 mm sphere.

Stair landings

Clear space is needed to the head and foot of any stair flight to allow people to move between a flight and an adjacent level surface safely. People may also wish to pause on stairs, particularly during ascent, and any intermediate landing should provide a temporary respite and be of a size to allow this whilst still permitting others to pass safely.

A stair landing should:

• be provided at the top and bottom of every flight. A single landing may be common to 2 or more flights; and
• be level except, in external locations, for any minimal crossfall necessary to prevent standing water; and
• have an effective width of not less than the effective width of the stair flight it serves; and
• be clear of any door swing or other obstruction, other than to a private stair , as noted below.

The minimum length of a stair landing, measured on the centreline of travel, should be either 1.2 m or the effective width of the stair, whichever is less. However where, on an intermediate landing, a change of direction of 90º or more occurs, the centreline length need not be measured if the effective width of the stair is maintained across the landing. On landings to external stair flights , where tactile paving is used, the minimum length of landing should be 1.2 m.

Other than at an accessible entrance, a landing need not be provided to a flight of steps between the external door of:
• a dwelling and the ground, balcony, conservatory , porch or private garage, where the door slides or opens in a direction away from the flight and the total rise is not more than 600 mm; or
• a dwelling , or building ancillary to a dwelling , and the ground, balcony, conservatory , or porch , where the change in level is not more than 170 mm, regardless of method of door operation.

On a private stair , other than on an intermediate landing, common to 2 flights
• a door to a cupboard or duct may open onto a top landing if, at any angle of swing, a clear space of at least 400 mm deep is maintained across the full width of the landing.
• a door may open on to a bottom landing, if, at any angle of swing, a clear space of at least 400 mm deep is maintained across the full width of the landing and the door swing does not encroach within space designated for future installation of a stair lift.

Stair flights consisting of both straight and tapered treads. On that part of a flight consisting of tapered treads, the going of the tapered treads should be uniform and should not be less than the going of the straight treads. At the inner end of the tread, the going should be at least 50 mm. Tapered treads on a stair should be constructed in accordance with BS 585: Part 1: 1989, Appendices B1 and B3, irrespective of material or whether it contains open rises.

In a flight less than 1 m wide the going should be measured at the centre line of the flight as described in clause 4.3.1. In a flight 1 m wide or more the going should be measured at 2 points, 270 mm from each end of the tread, as described in clause 4.3.1 and the minimum going should be at least the going of the straight treads.

Handrails to stairs and ramps

Handrails to a stair and ramp flights will provide support and assist safe passage. As the full width of a flight may be used, either by people passing or by person who favours one side, a handrail should generally be provided to both sides of a stair or ramp flight. A handrail should be provided to both sides of any flight where there is a change of level of more than 600 mm, or where the flight on a ramp is longer than 2m.

However:
• handrails may be omitted to the flight of a ramp, serving a single dwelling, where the change in level is less than 600mm; and
• a handrail need only be provided to one side on a flight of a private stair.

Where a handrail is provided to only one side of a private stair flight, the side on which a handrail is not fixed should permit installation of a second handrail at a future date. A second handrail will provide additional support to a person using the stair and may be installed provided a clear width of 800 mm is maintained.

The extension of a handrail at landings allows an individual to steady themselves before ascending or descending. For a person with impaired vision, the change in slope of the handrail and its return into a wall can also signal the start or finish of a flight. A handrail on a stair or ramp flight should:

a. extend at least 300 mm beyond the top and bottom of the flight as shown in the diagram above. However the 300 mm extension may be omitted where the handrail abuts a newel post; and
b. have a profile and projection that will allow a firm grip; and
c. end in a manner, such as a scrolled or wreathed end, that will not present a risk of entrapment to users; and
d. contrast visually with any adjacent wall surface.

However, only sub clause b. need be provided on a private stair or to a ramp providing access within a single dwelling , as users are likely to be familiar with the layout and use of the flight. A stair or ramp that is more than 2.3 m wide should be divided by a handrail, or handrails, in such a way that each section is at least 1.1 m and not more than 1.8 m wide. This does not apply to a stair between an entrance door to a building and ground level, where not forming part of an escape route.

Height of handrails

A handrail should be fixed at a height of at least 900 mm and not more than 1.0 m, measured vertically above the pitch line of a flight on a stair or ramp and on a landing where a handrail is provided.

Headroom on stairs and ramps

A flight or landing on a stair or ramp should have clear headroom of at least 2.0 m extending over the whole of the effective width. Height should be measured vertically from the pitch line of the flight or from the surface of the landing.
In a dwelling where any portion of a flight or landing lies outside the area needed to maintain the effective width of a flight or landing, a reduction in headroom may be considered, provided that no dangerous obstructions or projections are created.

Head room = 2m vertically from pitch line
Max number of risers = 16
Min number of risers = 2
Landings top and bottom of stairs same width as stairs

Detail

Max Rise (R)= 220mm
Min Going (G) = 220mm
Max pitch = 42 degrees
Formula = (2R+G) between 550mm and 700mm
Common stair dimensions are 200mm risers and 225 goings

Width of Stairs

Clear width of stairs = 800mm
600mm if access is to a single room not being a kitchen or living room

Handrails:

on one side for stairs 1m or less
on both sides for stairs greater than 1m
between 900mm and 1m high

Balustrades:

Balustrades are to be constructed so that a child cannot easily climb them i.e. they should be vertical.

All openings in the staircase should be smaller than 100mm. i.e. so that a ball of 100mm diameter cannot pass through the gap. (The space formed by the tread, riser and the pitch line may be ignored.)

Please check with your local building control department before using information contained in this page to ensure that they comply with your local building codes.