The building regulations fire-safety requirements remain the legal duties, with the Approved Document setting out the published compliance approach. [1] [2]
Check the correct height and building type
This provision concerns blocks of flats and the height of the top storey as defined in the guidance. It is not simply a roof-ridge measurement and should not be substituted for the separate definition of a higher-risk building. The HRB regime uses height or storey-count criteria together with the building's use. [1] [3]
Have the fire designer identify the applicable measurement and escape strategy on the drawings. A label such as “six-storey building” does not, on its own, answer either regulatory question. [1] [3]
Two stairs must work as a designed system
The guidance also calls for more than one common stair where its other single-stair conditions are not met. Consequently, being below 18 metres does not guarantee that a single-stair arrangement is acceptable. Assess the complete escape design rather than treating the height threshold as the only requirement. [1]
Approved Document B states that interlocked stairs are regarded as a single stair for this purpose. Simply dividing one enclosure into two intertwined flights is not a way to count two independent common stairs. The relevant lobby, corridor and stair arrangements need to be coordinated in the fire strategy. [1]
Reserve the necessary space while the building layout is still being tested. Check the consequences for the accommodation schedule, accessible routes and shared circulation rather than attempting to insert another stair after all flats have been fixed. [4] [1]
The published transitional arrangements
The 2026 amendments set out protection for relevant building-control submissions made before 30 September 2026, provided the work was sufficiently progressed before that date or becomes sufficiently progressed within the following 18-month period. The precise conditions and type of submission must be checked for the project. [2]
For a new building, the document defines sufficient progress by reference to permanent foundation work, including pouring concrete for specified foundations or the start of permanent piling. For work to an existing building, it refers to that work having started. Planning permission alone does not meet these building-control transition tests. [2]
Keep dated evidence and obtain confirmation of the applicable position. Do not rely solely on a contract date, an intended start or a general statement that the site was “active”. [2]
Existing buildings and additional storeys
The change is not a blanket instruction to add a second staircase immediately to every existing occupied block. Proposed building work, including upward extensions, needs to be assessed through the applicable building regulations and fire-safety arrangements. Establish the scope and transition rather than assuming either automatic exemption or automatic retrospective reconstruction. [1] [2] [5]
The Approved Document compilation also contains separately identified future amendments. Its fire-resistance classification changes take effect from 2 September 2029, subject to their own transition; they should not be confused with the staircase change already effective in 2026. [6]