External wall fire performance involves more than the visible cladding. Insulation, membranes, cavities, cavity barriers, fixings, subframes, window details and workmanship can all affect how the completed system behaves.
What makes the rules project-specific?
- The building’s height, use and occupancy.
- Whether the work is a new wall, a replacement or an alteration.
- The reaction-to-fire classification of individual products.
- Evidence for the complete wall build-up, not a visually similar system.
- Current Building Regulations and applicable transitional arrangements.
Documents worth asking for
Ask the designer, supplier or installer for the exact product declaration, classification reports and evidence supporting the proposed build-up. Product names and formulations can change, so match documents to the product code and version being supplied.
When to stop and get specialist help
For multi-occupancy, higher-risk, high-rise or otherwise complex buildings, do not use a consumer comparison page to decide suitability. A competent fire-safety and building-control team should assess the specific building and current regulations.