‘Second staircases’ to be mandatory for new buildings above 18m in England

The UK government has published long-awaited technical guidance (13-page / 252KB PDF) to provide details of its ‘second staircase’ policy, which is intended to improve building safety but has led to uncertainty in the property sector and resulted in developments being put on hold. The guidance, setting out changes to Approved Document B, makes second staircases mandatory in all new residential buildings over 18m in England from 30 September 2026.

Building safety expert Katherine Metcalfe of Pinsent Masons said: “The amendments to Approved Document B provide much-needed guidance on the purpose of the second staircase, and the layouts which will be permitted. It should allow the design of buildings to move forward with greater confidence that changes will not be required at a later date”.

In the government’s initial consultation in 2022, the proposal was to mandate two staircases in all new residential buildings in England above 30m in height. However, the final threshold of 18m has been introduced to provide alignment with the threshold for high-risk buildings under the Building Safety Act, the Fire Safety Act and other fire safety measures, according to the government’s response to the consultation.

The amendments to the document also require a second staircase for buildings in which flats are not separated from the common stair by a protected lobby, or where a maximum travel distance of 7.5m in one direction or 30m in multiple directions is exceeded. Under the revised rules, interlocked stairs should be considered as a single staircase.

The updated guidance does not require new buildings to have evacuation lifts, despite desire for wider provision of them from respondents during the consultation. Instead, it has included building design provisions to support the use of evacuation lifts in blocks of flats. The guidance states that where evacuation lifts are provided, these should be located within an evacuation shaft containing a protected stairway, evacuation lift and evacuation lift lobby. It also clarifies that an evacuation lift lobby should provide a refuge area for those waiting for the evacuation lift, have direct access to a protected stairway and not be directly accessible from any flat, maisonette, storage room or electrical equipment room.

Property developers will have a 30-month transitional period from the publication of the guidance, which was on 29 March, to comply with the new requirements.

During the transitional period, new building regulations applications can conform to either the previous guidance or the updated guidance requiring a second staircase. When those 30 months have elapsed, all applications will need to conform to the new guidance, meaning second staircases will become mandatory. Any approved applications that do not follow the new guidance will have 18 months for construction to commence. If construction is not underway after 18 months, a new building regulations application following the new requirements will have to be submitted.