The two staircase requirement in England

The introduction of the two staircase requirement in England should not come as a surprise to the construction industry.  Back in September 2024, as part of the roll out of a package of fire safety measures and reforms to ensure the safety of residents, the Government issued a circular and accompanying revisions to Approved Document B (Fire Safety) to apply to building work in England. 

The revisions included the requirement for more than one staircase for taller residential buildings, set to come into effect Wednesday 30 September 2026, subject to transitional provisions. 

Updates to Approved Document B have also now been published to introduce guidance on second stairs and evacuation lifts in taller residential buildings. 

When does the two staircase requirement apply? 

Since 2023, a requirement for at least two staircases has applied to residential developments over 30m seeking planning approval from the Greater London Authority.  

This latest requirement for more than one staircase applies where: 

• The building has a top storey of 18m or more in height; or 
• A flat is on a storey that does not meet the criteria for a single escape route or a small single stair building referred to in paragraphs 3.27 (Design for horizontal escape) and 3.32 (Small single stair buildings) of Approved Document B.  Approved Document B provides that a person escaping through a common area, if confronted by the effects of a fire in another flat, should be able to turn away from it and make a safe escape via an alternative route and applies limits on the distance in common areas of blocks of flats to travel to a storey exit or stair lobby.  Notably, interlocked staircases, sometimes referred to as scissor stairs or stacked stairs, will be considered as a single escape route and not an alternative means of escape.  

What are the transitional provisions? 

Acknowledging the challenging economic climate at the time, the industry was given a lead in time of 30 months for this change.   

The enhanced requirements for at least two staircases do not apply to works where a building notice or an initial notice has been given to, or a building control approval application with full plans has been made to, the relevant building control authority before 30 September 2026 and either the building work to which it relates: 

• Has started and is sufficiently progressed before that day; or 
• Is started and is sufficiently progressed within 18 months of that day i.e. by 30 March 2028. 

What constitutes the works being “sufficiently progressed”? 

A term previously used when the dutyholders regime and the higher risk building (HRB) control regime was introduced back on 1 October 2023, “sufficiently progressed” means: 

• Where the building work consists of the construction of a building, when the pouring of concrete for the permanent placement of the trench, pad or raft foundations has started, or the permanent placement of piling has started; or  
• Where the building work consists of work to an existing building, when that work has started; or  
• Where the building work consists of a material change of use of a building, when work to effect that change of use has started.  

For HRBs, section 9 of the Building (Higher-Risk Buildings Procedures) (England) Regulations 2023 requires that two notices are given at the start of the building works: 

• Notice of the intention to start the work and the date that work is to start: to be given at least five working days before the day on which the work starts (Regulation 9(2)).  A shorter period of two working days applies for non-HRBs under Regulation 16(1) of the Building Regulations 2010.
• Notice of day on which the work is to be regarded as commenced: to be given not more than five working days after commencement (Regulation 9(3)). 

Viability 

While we can all agree that safety is absolutely paramount but we must address the elephant in the room  - viability. These changes are being implemented in a challenging market and the addition of a second staircase to a residential building inevitably reduces the net lettable or saleable area on each floor.  This reduction in saleable area, combined with the additional construction costs associated with building a second staircase, can have a material impact on the overall viability of a development, particularly for schemes that were already operating on tight margins. 

From a planning and buildability perspective, the two staircase requirement underscores the need for early-stage design integration.  Developers who have not yet factored a second staircase into their designs may face the prospect of returning to the planning authority with amended proposals, which can result in delays and additional costs.  

The implications for retrofit and refurbishment projects deserve particular attention.  Where an existing building is being converted or refurbished and the works trigger the two staircase requirement (for example, a material change of use to residential), the structural constraints of the existing building may make the installation of a second staircase extremely difficult or prohibitively expensive.  Unlike new-build projects, where the second staircase can be designed into the building from the outset, retrofit projects must work within the limitations of the existing structure, which may offer limited flexibility for routing a second staircase through the building.   

Next Steps 

With other factors such as stakeholders’ requirements being taken into consideration, some applicants may have opted for multiple staircases notwithstanding that that the development is expected to come within the transitional provisions.  For others, coming within the transitional provisions may determine whether or not the development remains viable.  For those applicants who have yet to secure their building control approvals, there will understandably be some nervousness around whether approval will be secured or whether they will be forced to resubmit applications after the critical date of 30 September 2026 (taking the development outside of the transitional provisions).   

The majority of new developments affected by this new requirement will be HRBs proceeding through the building control gateway regime, specifically, Gateway 2.   

In the latest gateway data published by the Government for the period June to August 2026, the approval rate for new HRBs and conversions was at an impressive 92% (with 5 of the 147 in progress cases having been invalidated or withdrawn).  The median approval time for those cases remains far in excess of the 12 week period specified in the relevant Regulations for processing new build Gateway 2 applications, at 22 weeks.   

For the unsuccessful minority of applicants, finding themselves subject to an additional second staircase requirement is not the end of the bad news, unfortunately.  They may also find themselves subject to the Building Safety Levy (England) Regulations 2025 (as amended) if they resubmit their Gateway 2 application after the date of introduction of the building safety levy on 1 October 2026.   

Other jurisdictions - including Scotland, Australia, and the United States - have long required multiple means of egress for tall residential buildings. England was, until recently, an outlier in permitting single-staircase designs for tall buildings. Looking ahead, there is a realistic prospect that the 18-metre threshold for the two-staircase requirement may be lowered, potentially aligning with an 11-metre threshold, and that the requirement could be extended to other building types such as hotels, care homes, and student accommodation. Developers and their advisers should monitor these developments closely and adopt a precautionary approach in design. 

For more developments and insights on Building and Fire Safety, please see here.