UK staircase building regulations explained

Staircases in the UK must comply with Building Regulations to ensure they are safe, comfortable, and practical to use.

These regulations affect step sizes, pitch, headroom, balustrades, and layout. Designing with compliance in mind from the start helps avoid costly changes later in the project.

This page explains the key staircase regulations in plain English and how they affect real staircase design.

Which staircase regulations apply?

Most domestic staircases in England and Wales are governed by Approved Document K of the Building Regulations.

In Scotland, staircases are covered under Section 4 – Safety of the Scottish Building Standards.

While the principles are similar, there are differences in specific requirements, so it’s important to design for the correct jurisdiction.

This page focuses on general UK domestic guidance. Local Building Control always has the final say.

Rise and going

Building Regulations control the maximum height of each step (rise) and the minimum depth of each tread (going).

These dimensions work together to control comfort and safety.

Typical domestic rise is around 190–210mm
Going is commonly 220–250mm
The relationship between the two must satisfy the 2R + G rule
Understanding rise & going → Rise & Going page
Minimum going 220mm ( Domestic Staircase) (225mm in Scotland)
Maximum Rise Height 220mm ( Domestic Staircase)

Staircase pitch

Staircase pitch is the angle of the stair relative to the horizontal.

For most domestic staircases, the maximum permitted pitch is approximately 42 degrees.

Designing close to the maximum pitch may comply with regulations but can feel steep in daily use. Where space allows, a lower pitch improves comfort.

Headroom requirements

Headroom is the vertical distance measured from the pitch line of the staircase to the underside of the ceiling or any obstruction above.

This is not measured directly above individual treads.

Headroom problems often occur:

Near the bottom of the staircase
Where stairs pass beneath ceilings or landings
In loft conversions or roof spaces

Some allowances may apply in loft staircases depending on location and use.

Minimum Headroom 2 Metres

Staircase width

In England and Wales, Approved Document K does not specify a minimum staircase width for most domestic staircases.

Instead, staircase width is left to the designer, provided the stair is safe, practical, and compliant with other requirements such as handrails and balustrades.

In practice, a width of around 860mm overall is commonly used for domestic staircases.

This typically results in a clear walking width of approximately 800mm once handrails are installed, which most people find comfortable for everyday use.

Wider staircases

Staircases over 1000mm wide generally require handrails on both sides to comply with safety guidance.

This should be considered early, as additional handrails affect usable width, detailing, and cost.

Loft and space-restricted staircases

In loft conversions and other space-restricted situations, narrower staircases may be permitted.

As a practical minimum, we recommend aiming for at least 600mm clear width where possible, while ensuring handrails and balustrades remain compliant.

Narrower staircases can be acceptable in specific circumstances, but comfort and usability should always be considered alongside compliance.

Scottish regulations

In Scotland, Building Standards set minimum width requirements, which vary depending on location and use.

As a general guide:

900mm minimum may apply in certain situations
800mm minimum may apply elsewhere, subject to layout and access

Staircases in Scotland should always be designed to meet the relevant Scottish Building Standards for the specific application.

Local authority interpretation can vary, so early confirmation is recommended.

Design considerations

When choosing staircase width, also consider:

How handrails reduce the usable walking width
Furniture movement
Door positions at the top and bottom of the stair
Whether the staircase serves as a main access route or a secondary stair

Balustrades and handrails

Staircase regulations include requirements for handrails and balustrades to reduce the risk of falls and ensure safe use.

Balustrade safety

Balustrades must be designed to prevent a 100mm sphere from passing through at any point, to reduce the risk of children falling through.

This applies to:

Stair flights
Landings
Galleries and void edges

Open stair designs must still meet all guarding and safety requirements, regardless of appearance.

Handrail height – domestic staircases (England & Wales)

For most domestic staircases in England and Wales:

Stair handrails are typically positioned between 900mm and 1000mm above the pitch line
Handrails on landings are typically at least 900mm high

Balustrade and guarding height

A balustrade or guarding is generally required where there is a drop of more than 600mm.

This includes:

Open sides of staircases
Landings
Gallery edges

Structural performance of balustrades (important)

In addition to dimensional requirements, balustrades must be capable of resisting horizontal loads.

As a general guide:

Domestic staircases are designed to a lower horizontal load requirement
Commercial staircases are designed to a higher load requirement, reflecting increased use and risk

Typical values used in design may include:

Lower loads for domestic use
Higher loads for commercial or public staircases

The exact load requirements depend on the building use class and are defined under structural standards such as BS EN 1991-1-1 (Eurocode) and associated guidance.

Final confirmation should always be made at the design stage for the specific application.

Commercial staircases and galleries

For commercial staircases and galleries, additional requirements commonly apply, including:

Higher balustrade load ratings
Minimum guarding heights of 1100mm on landings and gallery edges
Increased handrail requirements depending on width and occupancy

These requirements vary by use and location and should always be confirmed with Building Control.

Designing with compliance in mind from the outset avoids costly redesigns later.

Open riser staircases

Open riser staircases are permitted in the UK, provided safety requirements are met.

This is commonly achieved by:

Limiting the gap between treads
Using thicker treads
Adding downstands or other detailing

Open riser designs must still prevent the passage of a 100mm sphere.

Open Plan Staircases → Open Plan Staircases page

Replacing an existing staircase

When replacing an existing staircase, Building Control may accept layouts that improve on the original design, even if full modern compliance cannot be achieved.

Each case is assessed individually, and early discussion with Building Control is recommended.

Loft staircase regulations

Loft staircases often have different constraints around headroom, width, and layout.

While some allowances may apply, safety remains the priority, and design decisions should be made early to avoid planning issues later.

Alternating tread staircases (space saver stairs)

In England and Wales, Approved Document K allows the use of alternating tread staircases (sometimes referred to as space saver stairs) in limited circumstances.

When alternating tread staircases are permitted

Alternating tread staircases are only permitted where:

The staircase provides access to a single habitable room, such as a loft bedroom or study
There is insufficient space to install a conventional staircase that complies with normal requirements

They are not permitted as the main access staircase to a dwelling.

Use limitations

Alternating tread staircases are intended for infrequent use and are not suitable where:

Regular daily access is required
The staircase serves multiple rooms
The staircase forms part of the main circulation route

Dimensional requirements

Alternating tread staircases have their own dimensional rules, which differ from conventional staircases.

These typically include:

A steeper pitch than standard staircases
Specially shaped treads designed for alternate foot placement
Restrictions on minimum tread dimensions and overlap

Exact dimensions must comply with Approved Document K and should be confirmed at the design stage for the specific application.

Handrails and guarding

Alternating tread staircases must still comply with handrail and guarding requirements, including:

A handrail positioned at an appropriate height
Guarding to open sides and landings
Protection against falls where there is a drop of more than 600mm

Due to the steeper pitch, secure handrails are particularly important.

Headroom considerations

Headroom requirements may be reduced in certain loft staircase situations; however:

Safe access must still be provided
Pinch points should be identified early
Building Control approval is required

Headroom allowances vary depending on layout and location.

Scotland does NOT permit alternating tread staircases in the same way as England & Wales
Scottish standards are significantly stricter