Regulatory update

Approved Document B: the September 2026 changes explained

The 2026 amendments to Approved Document B took effect on 30 September 2026 in England, subject to transitional arrangements. They update guidance on escape in blocks of flats, including second stairs and design provisions to support evacuation lifts. For property and project teams, the first task is to establish which edition applies to the proposed work.

What has changed?

The amended guidance recommends more than one common stair for blocks of flats with a top storey 18 metres or more in height, using the Approved Document’s measurement method. It also sets out design provisions for evacuation shafts and lobbies where evacuation lifts are provided. Interlocked stairs count as a single escape route. The provisions should be read together with the guidance on protected routes, smoke control and fire doorsets.

Review the updated escape provisions with the design team
Use the correct storey-height measurement
Coordinate stairs, lobbies, doorsets and smoke control

Which projects can use the earlier guidance?

The previous edition, including the 2020, 2022 and 2025 amendments, can continue to apply where the relevant building notice, initial notice or building control approval application with full plans was submitted before 30 September 2026, and the work was sufficiently progressed before that date or becomes so within the following 18 months. For a new building, this means starting permanent foundation concrete or permanent piling; work to an existing building or a material change of use has its own start criteria. Check the official wording and project records with the relevant building control body.

Check the type and date of the notice or application
Retain evidence of qualifying construction progress
Confirm the applicable edition before procurement

Does every existing block need a second staircase?

The amendment is not a blanket instruction to retrofit a second stair to every existing occupied block. Approved Document B gives guidance on meeting Building Regulations requirements for building work. Relevant work to existing buildings, including alterations and material changes of use, can still bring those requirements into play. Existing-building fire risk management remains a separate, continuing responsibility. Ask the competent designer and relevant building control body to establish the requirements for the particular scope; avoid treating either “existing” or “new” as a complete answer.

Distinguish proposed building work from ongoing management
Review the building’s fire strategy and risk assessment
Seek project-specific advice for alterations or conversions

Keep the 2026 and 2029 changes separate

The September 2026 update should not be described as the general withdrawal of BS 476 fire-resistance classifications. Removal of those national classifications from Approved Document B is scheduled for 2 September 2029, with separate transitional provisions. Changes to reaction-to-fire and roof classifications already took effect in March 2025. These are different performance categories and dates; a product specification needs the correct classification and supporting evidence for its intended use.

Separate reaction to fire from fire resistance
Check current requirements rather than future text alone
Verify the manufacturer’s evidence for the proposed product

What should property and construction teams do now?

Record the applicable guidance edition alongside the agreed fire strategy. Review door schedules, protected-route interfaces and compartmentation details before work is ordered or concealed. FireX can support the agreed passive-fire scope through fire-door installation and maintenance, fire stopping and compartmentation work, with traceable records. The project’s designer and dutyholders should define the required performance; completion records should show what was installed, where, and against which specification.

Confirm door and compartmentation requirements before ordering
Resolve uncertain interfaces before installation
Keep photographs, product references and installation records together

Next steps

Relevant services and guidance

Continue with the FireX service, sector or location information most relevant to your building.

Original sources and further reading

General guidance

This article is general information, not legal, fire-engineering or product-design advice. Follow the building fire strategy, current official guidance, tested system evidence and competent professional advice.

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