Approved Document B 2026 Changes: Second Staircases and Evacuation Lifts

What Is Approved Document B?

Approved Document B is the government’s statutory guidance on meeting the fire safety requirements of the Building Regulations 2010 in England. It comes in two volumes:

• Volume 1: covers dwellings, including blocks of flats.
• Volume 2: covers buildings other than dwellings.

It sets out what, in ordinary circumstances, may be accepted as one way to comply. You can take a different approach, but you’ll need to show it meets the regulations and agree it with your building control body early. For higher-risk buildings, that’s the Building Safety Regulator.

The government first published these amendments in March 2024 and reissued them in September 2024. They came out of a consultation that ran from December 2022 to March 2023. GOV.UK now hosts updated versions of both volumes with the 2026 changes built in.

What Has Changed for Second Staircases?

The amended Volume 1 says flats should be served by more than one common stair if either of these applies:

• the building has a top storey of 18m or more in height; or
• the flat is on a storey that doesn’t meet the criteria for a single escape route or a small single stair building.

The guidance now states that a single common stair arrangement is only suitable for buildings with a top storey under 18m.

How Is the 18m Measured?

Approved Document B measures the height of the top storey from the upper floor surface of the top floor to ground level on the lowest side of the building (Diagram D6). Roof-top plant areas, and any top storeys made up only of plant rooms, don’t count.

What Else Does the Stair Guidance Cover?

• Interlocked stairs count as one: interlocked stairs, also called scissor or stacked stairs, count as a single escape route, not an alternative means of escape.
• Minimum width: common stairs in a building with a storey of 18m or more, and firefighting stairs, should be at least 1100mm wide. That’s the clear width between walls or balustrades.
• Separate routes: an escape route shouldn’t pass through one stair enclosure to reach an alternative exit. It can pass through one stair’s protected lobby (minimum REI 30), but a protected lobby shouldn’t give direct access to more than one stair.
• Divided corridors: where a common corridor connects two or more storey exits, a self-closing fire doorset (minimum E 30 Sa) should divide it. Position the doors so smoke can’t affect access to more than one stair.

What Does the Guidance Say About Evacuation Lifts?

Start with what it doesn’t say: the amendments don’t make evacuation lifts mandatory. They set out how to design the building where evacuation lifts are provided. An evacuation lift is a lift that may be used to evacuate people in a fire. It matters most to residents who can’t use the stairs, so the guidance aims to give the lift the same protection as the stair beside it. Where a building has evacuation lifts:

• They should sit inside an evacuation shaft: a protected shaft containing a protected stairway, the evacuation lift (with its machine room) and evacuation lift lobbies.
• The lobby is a refuge: the evacuation lift lobby should give people waiting for the lift a refuge area, have direct access to a protected stairway, and not be directly accessible from any flat, maisonette, storage room or electrical equipment room.
• Same protection as the stair: evacuation shafts should get at least the same level of protection as the stairway. Any smoke control system designed to protect the stair should extend the same protection to the evacuation lift and its lobby.
• Fire doors to match: doors forming part of the enclosure of a protected stairway or evacuation shaft, or of a protected lobby leading to one, should achieve at least E 30 Sa.

Both volumes also gain new definitions for evacuation lift lobby, evacuation shaft and interlocked stair, plus an updated definition of storey exit that now includes a doorway giving direct access into an evacuation lift lobby within an evacuation shaft. In Volume 2, these definitions are the only changes.

Do the Changes Apply to Projects Already Underway?

Not necessarily. Transitional arrangements let some projects carry on under the previous edition (the 2019 edition incorporating the 2020, 2022 and 2025 amendments). A project qualifies only if both of these are true:

1. Before 30 September 2026, a building notice or initial notice was given, or a building control approval application with full plans was made, to the relevant authority.
2. The building work had started and was sufficiently progressed before 30 September 2026, or it starts and is sufficiently progressed within 18 months beginning on that day.

“Sufficiently progressed” has a set meaning:

• New buildings: the pouring of concrete for the permanent placement of trench, pad or raft foundations has started, or the permanent placement of piling has started.
• Work to an existing building: that work has started.
• Material change of use: work to make that change of use has started.

If a project doesn’t meet both conditions, the amended guidance applies. The 18-month window closes in late March 2028, so schemes submitted in time that haven’t yet reached foundations or piling should check where they stand now.

What About Existing Buildings?

Approved Document B guides building work. These changes don’t ask owners of existing blocks to retrofit a second staircase. But work to an existing building, and a material change of use (such as converting offices into flats), both count as building work, so the new guidance can apply to them.

What the Changes Mean for Fire Protection

More staircases and evacuation shafts mean more protected shafts, more fire-resisting construction and more fire doorsets, and every one of them only works if it’s built exactly as designed. That means compartmentation that holds, fire stopping that seals every service penetration, and smoke control that now has to protect the evacuation lift and lobby as well as the stair.

That’s the work we do. We install and remediate passive fire protection, including fire stopping and compartmentation, on residential buildings nationwide, and we deliver active systems such as automatic opening vents and disabled refuge communication alongside it. We’re FIRAS accredited, and we record every installation through Onetrace, so you can show exactly what went in, where and how, and drop that evidence straight into the building’s golden thread.

If you’re designing or delivering a residential building of 18m or more, talk to us early about the passive fire protection and smoke control the new layout needs.

Where to Find the Official Guidance

• Fire safety: Approved Document B (GOV.UK)
• 2026 amendments to Approved Document B, volumes 1 and 2 (PDF)
• Circular letter: new updates to Approved Document B (September 2024)

Always check the current version on GOV.UK before acting on any of this.