08 Dec, 2023

1. Introduction - The Fifth Façade

Modern building design has witnessed a significant expansion in the role of roofs. Flat roofs now accommodate not only plant and HVAC equipment but also house renewable energy infrastructure, social spaces, and more. This evolution occurs amidst a backdrop of consistent roof fire rates, drawing increased attention to the risks associated with combustible building materials post the Grenfell Tower fire. While legislation has been amended, predominantly banning combustible materials in external walls of relevant buildings over 18m, this prohibition doesn't fully extend to roofs, leaving this aspect outside the fire protection scope.

A whitepaper, 'Flat Roofs: Managing Fire Risk in the Fifth Façade,' delves into industry misconceptions surrounding testing protocols and fire safety credentials. The paper advocates using the A1 to F Euroclass reaction-to-fire classification system for identifying non-combustible materials. It emphasizes the importance of incorporating non-combustible insulation materials in flat roof constructions for compliance with fire safety requirements.

As multifunctional flat roofs become increasingly relevant, this paper builds upon the insights from 'Flat Roofs: Managing Fire Risk in the Fifth Façade' to explore the fire safety implications of modern roofs and discuss best practices for identifying and mitigating risks.

2. Building Regulations and Guidance: Understanding Legislation

Meeting the statutory requirements of the Building Regulations is crucial for those involved in designing and executing building works. Confusion often arises between statutory requirements and the guidance provided in approved documents like Approved Document B (ADB) for fire safety in England. This is especially common in complex applications subject to different guidance for building types and heights, such as compartmentation and material reaction to fire requirements for façades and roofs.

ADB underscores that compliance with its guidance does not guarantee compliance with the regulations. In practice, designers must find solutions subjected to suitable fire resistance tests, ensuring the correct compartmentation and incorporating adequate fire-stopping measures to prevent the spread of fire and smoke.

The Building Safety Act 2022 reinforces liabilities for all stakeholders, emphasizing that following established practices may not be a valid defence. The Act extends limitation periods for claims under the Defective Premises Act, placing greater accountability on those involved in design and construction. Responsible parties must consider statutory requirements rather than relying solely on guidance. In relation to roofs and façades, designers should be vigilant regarding all potential fire risks, including those from below the roof. Modern construction methods and evolving technologies may require looking beyond regulatory guidance for best practices.