Review of Approved Document B: Fire Safety

Closes 17 Jun 2026

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9. Additional fire safety guidance for roofs

Approved Document B proposed updates

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9. Additional fire safety guidance for roofs

  1. Section 5 and 7 of Approved Document B Volume 1 and section 8 of Approved Document B Volume 2 provide guidance on roofs. As part of the continuous review of Approved Document B, BSR is reviewing the fire risk to modern roofs through several sources, including real fires investigations, construction technologies horizon scanning research, and engagement with industry bodies and standards-making committees. 

  2. Recent research looked to consider whether further guidance on fire stopping at junctions between modern roofs and compartment walls is needed. The proposed changes to this section of the guidance seeks to align the text style, improve legibility of diagrams, clarify definitions of roof components, and update guidance regarding fire stopping across compartment lines. 

Question 30: Do you agree that updated guidance more adequately considers modern roofs?
9. Additional fire safety guidance for roofs - continued

  1. The 2025 Future Homes and Buildings Standard builds on the 2021 Part L uplift and sets requirements for improved energy efficiency and low-carbon heating systems for new homes and non-domestic buildings to achieve ‘zero carbon ready’ status. Using solar energy will play a key role in the new standard, and it is expected that the uptake of photovoltaic (PV) panel installations will further increase. 

  2. BSR proposes fire safety updates in Section 12 for roofs incorporating energy generating installations.  It is also acknowledged that other standards are restricting placement of electrical equipment in common areas unless additional safeguards are applied. 

  3. Specifically, this means enhancing the fire performance of products beneath and around the installations. For flat roofs, certain conditional exemptions are provided if other fire safety measures are in place. Additionally, the provisions aim to limit the presence of panels near roof openings to mitigate the potential for fire spread.

Question 31: Do you have any comments on the draft guidance text?
Consultation Stage Impact Assessment

  1. The overall impact of the preferred policy is expected to be £28.9 million over a 10-year period, with an estimated net annual cost to business (ENACB) of £3.4 million per year. The cost of the updates to the guidance mainly falls on flats below 11m due to changes to the guidance for fire protection to flat roofs.

Question 32: Do you have views on what impact this text may have on industry?
9. Additional fire safety guidance for roofs - continued
  1. BSR proposes to undertake further research as required under the continuous review of Approved Document B to develop the understanding of modern roof performance and examine if a new testing standard is required. 
  1. This will include BSR conducting a full review of the current guidance on roofing to make sure testing standards are adequate and the guidance caters for the fire safety performance of modern roofs and accessory components.  
  1. BSR is committed to working with industry in developing improved awareness of PV panels on buildings including good design, installation and maintenance regimes.