What Makes a Commercial Staircase Part M Compliant?

Part M stairs are staircases designed so that people with reduced mobility, impaired sight or other disabilities can use them safely and independently, and in hotels, offices, shops and public buildings that duty shapes almost every dimension of the stair. For architects and developers, the challenge is that "Part M" means different documents in each jurisdiction, and its guidance for stepped access sits alongside the separate geometry provisions in Part K. This guide sets out what each regime asks of a commercial staircase, where the figures differ, and how a bespoke feature stair can meet them without losing its character.

What Part M Means for Stairs

Part M of the building regulations deals with access to and use of buildings. It does not replace the general stair guidance in Part K; it adds accessibility provisions on top of it, particularly for non-domestic buildings. Because stairs cannot serve wheelchair users, level access relies on lifts or ramps, and the stair provisions focus on people who walk with limited mobility and on those with sight loss.

England and Wales: Approved Document M

In England, Approved Document M Volume 2 covers buildings other than dwellings. Its section on stepped access sets detailed figures for rise, going, nosings, handrails and tactile paving, while paragraph 3.49 states that internal stairs satisfy the requirement if they follow the applicable guidance in Approved Document K. Wales publishes its own version of Approved Document M, which should be checked for Welsh projects.

Ireland: Technical Guidance Document M

In Ireland, Technical Guidance Document M (2022) covers access and use, including stairs suitable for ambulant disabled people. It cross-refers to Technical Guidance Document K for general handrail and guarding guidance, then sets out additional provisions that apply on accessible routes.

Scotland and Northern Ireland

Scotland covers stairs within Section 4 (Safety) in the Building Standards Technical Handbooks, with separate domestic and non-domestic volumes, while Northern Ireland uses its own technical booklets. Neither should be assumed to mirror England or Ireland exactly.

Key Accessibility Requirements for Commercial Stairs

The figures below come from the stepped access provisions in each document, which many designers also apply to internal feature stairs in public buildings. Paragraph references are for Approved Document M Volume 2 (paragraphs 1.33 and 1.37) and Technical Guidance Document M 2022 (sections 1.1.3.5 and 1.1.3.6).

Requirement	England: Approved Document M Vol 2	Ireland: Technical Guidance Document M
Rise	150 to 170 mm	150 to 180 mm
Going	280 to 425 mm	300 to 450 mm
Flight length	Maximum 12 risers where going is under 350 mm; 18 where 350 mm or more	Flight rise up to 1500 mm, or 18 risers with a going of 350 mm plus
Nosing contrast	55 mm wide on tread and riser	50 to 65 mm, tread only
Open risers	Not permitted	Excluded, as are tapered treads
Handrail height	900 to 1000 mm over pitch line; 900 to 1100 mm at landings	900 to 1000 mm, measured from the pitch line
Handrail extension	At least 300 mm beyond top and bottom nosings	300 mm minimum at each end
Handrail profile	Round, 32 to 50 mm diameter, or 50 x 39 mm non-circular	Round, 40 to 50 mm, or oval of that width
Minimum width	1.2 m between enclosing elements	1200 mm clear

Rise, Going and Flight Length

Accessible stairs are shallower than domestic ones. Keeping every rise and going identical along a flight matters as much as the figures themselves, because an inconsistent step is a common trip hazard for anyone relying on rhythm rather than sight. Long flights need intermediate landings, and Approved Document M asks for landings with at least 1200 mm of unobstructed length.

Nosings and Visual Contrast

Both regimes require a permanently contrasting strip at each nosing so that the edge of every step is visible to people with impaired sight. Guidance from the UK Slip Resistance Group describes acceptable contrast as a difference of more than 30 points in light reflectance value between the two surfaces. Approved Document M also says a nosing should not project over the tread below, or by no more than 25 mm where a projection is unavoidable.

Handrails

Under the English guidance, each flight and landing needs a continuous handrail on each side, with additional rails dividing the flight into channels between 1 m and 1.8 m wide where the overall width exceeds 1.8 m. Rails should be easy to grip, stand clear of the wall (between 50 and 75 mm in Approved Document M) and continue past the first and last steps so a user is steady before the first tread and after the last.

Width, Landings and Warning Surfaces

External stepped access in both regimes needs a corduroy tactile surface at the head and foot of each run to warn of the level change, and single steps should be avoided. Inside, contrast, lighting and uninterrupted handrails do most of that work instead.

Lighting and Slip Resistance

Approved Document M points to BS 8300 for guidance on lighting stepped access, and good, even illumination with no glare on the treads makes nosing contrast far more effective. Surfaces matter too: the same group recommends a pendulum test value of 36 or more for low slip potential, which influences the choice of timber finish, inlay material and any anti-slip strip. Oiled or lacquered hardwood treads should be specified with the finish's tested slip performance in mind, particularly near entrances where wet footwear is likely.

Open Risers and Tapered Treads

Open risers catch toes and walking aids, while tapered treads give an uneven going, so both are excluded from accessible stepped routes. This is where many feature-stair concepts need rethinking, as floating and spiral forms often rely on exactly these details. Bavari's comparison of open riser vs closed riser staircases explains the wider trade-offs.

This article is general information only; building control, an access consultant or the project architect should confirm which provisions apply to a specific building, since use, occupancy and alternative accessible routes such as lifts all affect the requirement.

Designing an Accessible Feature Stair

Compliance does not have to mean a plain utility stair. A curved or sculptural design can still offer consistent rises, closed risers and a continuous rail, and timber lends itself well to the detail these rules demand. Contrasting hardwood inlays along every step edge, for example, can meet the visual contrast guidance while looking intentional rather than retrofitted, and an unbroken rail wreathed around landings satisfies both the rules and the eye. Bavari's article on hospitality staircase design shows how hotels and restaurants balance these demands with a strong visual identity.

The key is early coordination. When the access consultant, architect and stair maker agree rise, going, rail profile and nosing detail at concept stage, the design can be shaped around those limits rather than adjusted late, when changes are expensive. Glass balustrades, which suit many commercial interiors, should still carry a graspable rail that contrasts with its background.

How Bavari Fits Into the Process

Bavari designs, manufactures and installs bespoke stairs for hospitality, retail, office and residential development projects through its commercial stairs service, using on-site 3D laser scanning, 2D shop drawings and 3D visuals before production. It works to the dimensions set by the design team and does not act as an access adviser, building control body or structural engineer, so compliance sign-off remains with those parties. Specifiers can find more on the architects and interior designers page.

Frequently Asked Questions

What does Part M compliant mean for a staircase?

A Part M compliant staircase is one that meets the accessibility provisions of the relevant building regulations, such as Approved Document M in England or Technical Guidance Document M in Ireland, together with Part K. In practice, that means consistent shallow steps, contrasting nosings, closed risers, rails to either side that run past the flight, and adequate width. Building control, not the stair maker, confirms compliance for any given project.

Do commercial stairs need handrails on both sides?

Under Approved Document M Volume 2 in England, stepped access should have a rail running continuously along both sides of every run and its landings, with extra rails dividing very wide flights into channels. Technical Guidance Document M in Ireland also expects handrails on stepped approaches. Twin rails help people with more strength in one arm, and they guide blind and partially sighted users. Confirm the internal stair requirements for your project type with building control.

Is the Disability Discrimination Act still relevant to stair design?

In Great Britain, the 1995 disability discrimination legislation was largely replaced by the Equality Act 2010, which requires service providers to make reasonable adjustments for disabled people. The older law remains in force in Northern Ireland, while the Republic has its own Disability Act 2005. These laws sit alongside building regulations rather than setting stair dimensions, so designers normally use Part M guidance and British Standard BS 8300 as the practical reference point.

Plan Your Commercial Staircase With Bavari

If you are specifying a feature stair for a hotel, office, retail space or mixed-use scheme, Bavari's team can work from your drawings to develop a design suited to the brief and the accessibility figures your consultants set. Contact Bavari to share drawings, discuss the project or request a quotation.