The majority of houses in the UK will have a least one staircase. Rather than being just a method of traversing multiple storeys of a house, the staircase is a key element of the interior design of a space. The materials used in its construction and the design chosen can have a big impact on the feel of interior space, especially in this age of open plan living.
Most staircases will be visible and part of a room, be that the hallway, basement, landing or living area.
As well as considering the design of a staircase it is important to understand the multitude of different building regulations and rules that pertain to staircases. If not designed and created correctly a staircase could cause a hazard to occupants. Below are some of the key considerations for staircase design on a private residential property. Buildings other than dwellings have slightly different regulations to consider.
Understanding Staircase Terms
Before we get into the regulations and rules it is important you understand a few keywords that crop up within building regulations and the associated standards.
The Tread = the horizontal surface of each step
The Rise = the height of each step, measured from the top surface of the tread to another
The Nosing = where the horizontal surface of the step overhangs the vertical structure of the riser
The Going = the depth of each step, measured from nosing to nosing
The Pitch = the overall angle of the slope of the staircase
A spiral stair = a stair in a helix around a central column
A helical stair = a stair in a helix around a central void
A Tapered Tread = a step in which the going reduces from one side of the step to the other.
For a full explanation of typical terminology used in bespoke staircase design read our article:
Some of the Regulations Listed in this Article
Building Regulations Part K
Part K of the Building Regulations provides the guidelines for ensuring occupants or visitors to a house are protected against falling, collision or impact.
The rules within Part K don't apply to Spiral or Helical Staircase designs. When looking at including a spiral staircase within your building project you instead need to consult the British Standards Document BS 5395 (see more below under 'Rules for Spiral or Helical Staircases).
Building Regulations Part M
Building Regulations Part M offers guidance and guidelines for the access of a building and the use of a building. Volume 1 is all about the rules required for dwellings (i.e private houses). It applies to all new build houses or houses that are 'undergoing a material alteration'.
Part M is split into 3 different sections depending on the type of accessibility you are designing the house for. Those sections are:
Section 1: Category 1 - Visitable Dwellings
Section 2: Category 2 - Accessible and Adaptable Dwellings
Section 3: Category 3 - Wheelchair User Dwellings
Both category 2 and 3 requirements are optional and used by architects or developers specifically looking to create this type of access to a building. Even though they are optional you may want to consider the recommendations in these later sections, especially if you are looking to create a house that will be used throughout a lifetime.
When undergoing works to a listed or historical building you are allowed a balanced approach to the compliance. You will have to consult the local authority conservation and access officers as well as English Heritage to gather advice.
BS 5395 Part 2 1984
This set of British Standards covers the basic requirements for the design and build of domestic spiral staircases.
Part K and M of Building Regulations apply to general staircase design however there is a caveat in them that states they are not applicable to helical or spiral staircases (which most architects use) instead these staircase designs need to be designed to the British Standard.
The Size of the 'Rise' and 'Going' in a Staircase
Building Regulations Park K dictates the required parameters for the steepness of a staircase. This applies to all internal and external staircases, excluding Spiral or Helical staircases.
For private staircases (stairs inside a private home):
2 x The Rise + The Going = 550 to 700mm
If you are undertaking building works to an existing building you should ensure that the above measurements are used. If this won't be possible because of restrictions within the fabric of the existing building you will need to speak to your building control body to agree an alternative design.
NOTE that if the external staircase is part of the principal entrance to the house or it is an alternative accessible entrance you also need to comply with the below guidance from Building Regulations Part M Section 1 and 6.
The Construction of the Staircase
Each stair tread must be level and the rise and going must be consistent up each flight.
Where you have an open riser in your staircase design - like the below image - the treads should overhang the rise by at least 16mm. You must also ensure that a 100mm diameter ball cannot pass through the open riser.
The Headroom Required for Staircases
You must allow a minimum of 2m headroom on all landings and between the Pitch Line and any structures above the staircase.
If you are undertaking a loft conversion and there isn't enough headroom to allow for the required 2m space Building Regulations Part K Diagram 1.4 offers an alternative option for a reduced clearance above the Pitch Line.
The Width of a Flight of Stairs
For accessibility, you should try to avoid a stepped level change on the entrance storey of a house. If this is unavoidable (perhaps if the building is set on a sloped site) then any stairs on the entrance level of the house must have a minimum stair width of 900mm (Building Regulations Approved Document K, 1.16).
The Length of a Flight of Stairs
If a staircase is made up of more than 36 risers in one consecutive line, then you must include at least one change of direction in the staircase. You can do this by including and separating the flight into two or more sections (like the below image).
Rules for Landings in Staircases
At the top of each flight of stairs, you must have a landing. A landing could be part of the upper floor of the house or part of the staircase structure. It should be kept clear of permanent obstructions. If needed you can have cupboard doors that open up onto the landing area but these should be kept closed/locked under normal conditions and when open these doors should allow at least 400mm of space on the landing between the doors and the edge.
Rules for Spiral or Helical Staircases
As listed above, all spiral and helical staircases must be designed in keeping with BS 5395 which covers the rules for domestic spiral staircase designs. The standard specifies different categories of stairs and their associated rules. Below are the categories of staircases for a residential project:
STAIRCASE CATEGORY: A
A small private stair intended to be used by a limited number of people who are generally familiar with stair for example an internal stair in a dwelling serving one room not being a living room or a kitchen, access stair to a small room or plant in an office, shop, factory, not used by the public, or fire escape for a small number of people.
Min/Max Rise Per Tread: 170-220
Min Clear Width Between Pole & Handrails: 600
Min Going Clear Centre of Tread: 145
STAIRCASE CATEGORY: B
A private stair similar to Category A, but also providing the main access to the upper floor of a private dwelling.
Min/Max Rise Per Tread: 170-220
Min Clear Width Between Pole & Handrails: 800 (900 in Scotland)
Min Going Centre of Tread: 190
Staircase Categories C, D and E are semi-public or public staircases for non-private residential projects.
By their very nature, helical and spiral stairs use tapered treads.
Approved Document K requires that if a staircase design uses consecutive tapered treads they should all have a consistent same going.
If a stair includes a mixture of straight and tapered treads, the going of the tapered treads should not be less than the going of the straight treads.
Building Regulations Part B (means of escape)
When looking at the staircase design of a project you may also have to consider Building Regulations Part B. This area of building regulations is regarding fire safety and ensuring occupants have an effective means of escape from all rooms in a building in the event of a fire. In some instances, the staircase may be the only effective means of escape.
Talk to an Expert
This article should be used as an outline guide only. Designing and building staircases is an expert game. You should always consult an expert before embarking on a project that includes the changing or building of a staircase.