Stair balustrade design – advice and technical guidance
Both performance and aesthetics are important considerations in stair balustrade design.
A stairwell or stairway is a space where furniture is largely or totally absent, so balustrade is usually the focal point which allows design expression and defines the overall look. When it forms part of a more open space – for example, providing access to a mezzanine floor – it can also be a striking signature feature. In that regard, it’s a building element that allows architects to explore their creative instincts, but first and foremost in any design formulation is the need for safety and regulatory compliance.
Designing balustrade for stairs, and any other part of a building, should meet performance requirements in accordance with BS 6180:2011 which gives recommendations and guidance for the construction of barriers in and around buildings which are designed to protect people from hazards. It provides a comprehensive guide to the design, structure, height and strength of barriers. Approved Document K is also a vital reference for stair balustrade design.
Document K states that guarding should be provided where it is reasonably necessary for safety to guard the edges of any part of a floor, balcony or any other place to which people have access. In the case of dwellings, guarding should be provided that is capable of preventing people from being injured by falling from a height of more than 600mm. For buildings other than dwellings the protection must be capable of preventing people from falling from a height of more than two risers.
Required height & width
Document K requires a minimum stair width of 1200mm between enclosing walls, strings and upstands. If the stairs are wider than 1000mm, a handrail is required on both sides. A minimum width of 1000mm is required between handrails (whether they are part of balustrade, wall-mounted, or both). If the flight is more than 2000mm wide, Document K recommends that it is divided into flights of minimum 1000mm wide, which can be achieved with a central balustrade/handrail.
Document K states that the height of the top of the balustrade (i.e. a handrail or top rail) should be 900mm – 1000mm from the pitch line of the floor for internal installations in residential stairs and landings. This applies to stair balustrade, stair guards and wall-mounted handrails. For external balustrades in residential and commercial environments, Document K recommends that the height of the balustrade top rail/wall-mounted handrail should be a minimum of 900mm for stairs. In buildings other than dwellings, if you provide a second (lower) handrail on a full-height structural guarding, the vertical height from the pitch line of the steps to the top of the lower handrail should be 600mm.
Horizontal Load Requirements
Stair balustrade must comply with Minimum Horizontal Imposed Loads which are determined by the type of use and intensity of activity. The below table outlines Minimum Horizontal Imposed Loads with loads relevant to stair balustrade indicated with an asterisk (*)
|TYPE OF ACTIVITY/|
OCCUPANCY FOR PART OF THE BUILDING STRUCTURE
|EXAMPLES OF SPECIFIC USE||HORIZONTAL|
UNIFORMLY DISTRIBUTED LINE LOAD (kN/M2)
|UNIFORMLY DISTRIBUTED LOAD APPLIED TO INFILL (kN/M2)||POINT LOAD APPLIED TO PART OF INFILL (kN)|
Domestic and residential activities
|(i)all areas within or serving exclusively within one dwelling including stairs but excluding external balconies and edges of roofs||0.36*||0.5*||0.25*|
|(ii) other residential (but also C)||0.74||1.0||0.5|
|B and E|
Offices and work areas not included elsewhere including storage areas
|(iii) light access stairs and gangways not more than 600mm wide||0.22*||N/A*||N/A*|
|(iv) light pedestrian traffic routes in industrial and storage buildings except designated escape routes||0.36||0.5||0.25|
|(v) areas not susceptible to overcrowding in office and institutional buildings also industrial and storage buildings except as given above||0.74||1.0||0.5|
Areas where people may congregate
Areas with tables or fixed seating
|(vi) areas having fixed seating with 530mm of the barrier, balustrade or parapet||1.5||1.5||1.5|
|(vii) restaurants and bars||1.5||1.5||1.5|
Areas without obstacles for moving people & not susceptible to overcrowding
|(viii) Stairs, Landings, Corridors, Ramps||0.74*||1.0*||0.5*|
|(ix)external balconies and edges of roofs. Footways and pavements within building cartilage adjacent to basement/sunken areas||0.74||1.5||1.5|
Areas susceptible to overcrowding
|(xi) theatres, cinemas, discotheques, bars, auditoria, shopping malls, assembly areas, studio. Footways and pavements greater than 3m wide adjacent to sunken areas.||3.0||1.5||1.5|
|(xii) all retail areas including public areas of banks/building societies or betting shops. For areas where overcrowding may occur, see C5||1.5||1.5||1.5|
|(xiv) pedestrian areas in car parks including stairs, landings, ramps, edges or internal floors, footways, edges of roofs||1.5*||1.5*||1.5*|
|(xv) horizontal loads imposed by vehicles||See clause 11|
Document K requires continuous handrails on each side of flights and each side of landings in buildings other than dwellings (and for common access areas in buildings that contain flats and do not have passenger lifts). In these types of buildings, you also need to ensure that handrails do not project into an access route and ensure that they contrast visually with their background without being highly reflective.
In dwellings, certain guidance applies in exceptional circumstances: where there is a stepped change of level within the entrance storey, perhaps on a severely sloping plot, then handrails are required on each side of the flight (if it comprises three or more risers) and each side of any intermediate landing.
In environments subject to excessively hot or cold temperatures, the surface of the handrail should have a low thermal conductivity – powder coating, commonly applied to metals such as aluminium, can achieve this. The handrail should be slip-resistant and the end of the handrail should be finished in a way that reduces the risk of catching on clothing. For the same reason, avoid handrails which include external screws or fixings.
In commercial and public buildings, you should consider DDA obligations in Part M of the Building Regulations. In accordance with Part M, BS8300 recommends a circular handrail with a diameter between 32 and 50mm. For more details on DDA compliance in handrails, please read our comprehensive handrail design guide here.
Balustrade can be fixed by various methods, including stanchions attached to the stair treads/steps with grouted-in bases (see A, below), flat plate bases (see B) or female socket bases (see C). If the stairway is narrow, particularly if it needs to accommodate frequent two-way flow of traffic, it’s often advisable to install the balustrade with side fixings (see D) attached to the vertical surface of the stair structure. This maximises available floorspace. If you are using structural glass balustrade, it should be installed with a similar side fixing method (see E). On flat surfaces, structural glass is generally secured within a floor channel, but this is usually complex and problematic in raked installations, so side fixing is a much easier solution.
Modern stair balustrade design is characterised by a host of aesthetic options. Infills provide plenty of variations . Two popular choices are rails (see 1, below) and – similar in style but more economical – tension wire (see 2). If used for the guarding of stairs in a building that may be used by children under five years of age, you need to ensure that a 100mm sphere cannot pass between the rails/wire. Alternative options such as glass panels (see 3) and perforated metal panels (see 4) take this consideration out of the equation. Structural glass balustrade – with free standing glass and no supporting stanchions – provides a stylish modern aesthetic (see 5). Make sure that glass is toughened and compliant with glass safety regulations which you can read about here.
Timber is seen as a traditional choice for stair balustrade design, but metal represents a more contemporary alternative that requires less maintenance. Powder coated aluminium (below left) is smooth to the touch and provides a non-chip, maintenance free finish for stanchions and handrails. It also combines well with glass panel infills. Neaco provide aluminium balustrade in a wood-effect finish to provide the natural aesthetic of timber without the drawbacks such as surface deterioration/damage and splintering. Satin polished stainless steel (below right) is also a maintenance free option providing a high aesthetic that combines well with glass too.
Stair balustrade design can be an engaging creative challenge which has the potential to enhance your overall design concept, but it can also be a complex task which benefits from expert guidance from experienced manufacturers and installers. For free advice in relation to the specific requirements for your project, please feel free to call Neaco’s technical team on 01653 695 721 or submit an enquiry on our Contact page.