How to specify public realm steps that meet building regulations

When specifying steps used by the public, it is important that the chosen step slabs, sometimes referred to as step flags, and step risers, form part of a design that will comply with the relevant building regulations to give safe access for their users.  

In England, specifiers must comply with Approved Document M of the building regulations, entitled ‘Access to and use of buildings’, and Approved Document K that covers ‘Protection from falling, collision, and impact’.  

Wales has its own versions of Parts M and K. In Scotland, building regulations cover the topic in Section 4.3 of the Scottish non-domestic Technical Handbook. Northern Ireland do so in Part H ‘Stairs, ramps, guarding and protection from impact’. ‘Access and Use’ in the Republic of Ireland is found in Technical Guidance Document M, and ‘Stairways, Ladders, Ramps and Guards’ in Technical Guidance Document K. 

As well as regulations, another source of useful information on specifying public realm steps is the standard BS 8300:2018 ‘Design of an accessible and inclusive built environment’.  

This standard focuses on maximising inclusivity for a wider range of visitors than the building regulations and applies across the whole of the UK. Meeting BS 8300 is not a legal requirement, and the standard goes beyond the minimum regulatory accessibility requirements. However, it does provide specifiers with useful examples of best practices for incorporation into designs that maximise accessibility and inclusion.  

These documents and standards provide specifiers with guidance on selecting the correct dimensions of step slabs, and step risers, to achieve regulatory compliance. However, it is always worth confirming with Building Control that the design and step products you have selected do indeed comply before installation begins. 

What are the key areas to focus on when specifying compliant public realm steps? 

There are several key areas to ensure that public realm steps deliver safe passage for users and do so in a way that achieves compliance with building regulations. 

 Tread and riser dimensions 

To ensure safe passage going up or down steps, minimum and maximum dimensions of the step slabs and step risers are set out within building regulations. The ‘rise’ of a step is the vertical measurement from one step to the next, and the ‘going’ is the depth of the tread from the front to the back. To ensure predictability for users these measurements must be consistent, and the risers should be closed to help prevent feet, or a walking aid, getting caught between the steps. 

Table 1 provides a summary; however, Building Regulations Ireland & Northern Ireland document Part K also needs referencing. For external steps, it states: “To ensure that the steps are suitably proportioned and comfortable to use, the rise and the going should be considered together. For comfortable gait, the sum of twice the rise plus the going (2R+G) should be between 550 mm and 700 mm, with an optimum of 600 mm.” 

Visually contrasting nosing strips 

Individual treads and risers need to be easily identified for users to be able to safely use a flight of stairs, and this is achieved by using visually contrasting nosing strips. 

Table 2 gives a breakdown of the dimensions of nosing strips for treads and risers.  

It should be used as guidance only as the government acknowledges that advice given by other expert bodies should be taken into consideration. For example, the Royal National Institute of Blind People (RNIB) Access Consultancy Services states that the ideal stair nosing dimension is 55mm on the tread, and 30-50mm on the riser. 

Light reflectance values 

The light reflectance value (LRV) is a measure of the visible and usable light that is reflected from a surface. Surfaces with a sufficient difference in LRV can be distinguished from each other by partially sighted people, and the general guidance in the building regulations states that a difference of 30 points in the LRV is enough to achieve sufficient contrast. 

Step slabs can be made of a number of different types of material such as granite, porcelain, and limestone in several colours and finishes. It is important that contrasting nosing strips are employed in each case that give the required contrast to meet the LRV requirements.  

Step Flags with Contrasting Nosing and Silver Granite Steps with Contrasting Nosing have an integral black nosing that provides the necessary 30-point difference. 

Slip/skid of step products 

Approved document M states: ‘Materials for treads should not present a slip hazard especially when the surface is wet’. It points the specifier to guidance on slip resistance given in Annex C of the BS 8300 standard.  

Nosing strips should be tested for slip resistance in both wet and dry conditions using the pendulum testing method in standard BS 7976-2:2002. Nosing that achieves a pendulum test value (PTV) of greater than 35 is classified as low risk. Both Tobermore’s granite aggregate step unit and the granite effect step slabs and risers in the Mayfair range exceed this with a PTV in excess of 45. 

Use of tactile paving surfaces 

Approved Document M has a section called ‘Aids to communication’ which looks at the design considerations that can provide information to visually impaired people to help them safely identify and use access routes. This includes the use of tactile paving slabs.  

Detailed guidance on surface finishes is available in BS 8300 and the Department for Transport (DfT) document ‘Guidance on the use of Tactile Paving Surfaces’.  

A corduroy surface is shown here in Figure 16 taken from the DfT guide.

This surface is used to warn visually impaired people of a hazard so they can proceed with caution. 

 The corduroy surface should: 

• Extend across the full width of step flags at the top and bottom of the flight 

• Where possible start 400mm from the first nosing to give people time to adjust their speed  

• Be laid to a depth of 800mm if the steps are in the direct line of walking travel 

• Extend 400mm beyond the width of the steps on either side to allow for people approaching the steps at an angle 

As detailed in Figure 17 from the same DfT guide. 

Tobermore has Blister, Cycleway, and Hazard patterned tactile slabs to assist pedestrians who are visually impaired in public realm spaces. 

 Where can I learn more about specifying steps in public realm spaces? 

We at Tobermore are experienced in supplying steps and paving slabs for use in public realm spaces. 

Regarding specifying steps in public realm spaces Craig McBride, Tobermore’s Technical and Product Training Manager, comments:

“There are several regulations and standards that apply in this area. We have compiled a CPD to raise awareness of the key points, and our technical experts are available to help advise on solutions that will meet your project requirements. With this support, accompanied by our range of products, we can help customers specify safe and compliant step solutions” 

Request the Steps CPD that explores the subject in greater detail, or contact our technical team if you require any assistance when specifying steps in public realm spaces.