What is combustible cladding?
Certain types of cladding can burn rapidly if it catches alight. Problems with metal composite panels and insulated cladding systems relate mainly to multi-storey buildings because of the potential for rapid fire spread via the external areas of the building. These products can ignite easily and melt at relatively low temperatures.
It is important to note that the presence of external combustible cladding on a building does not necessarily mean it is a fire hazard. It depends on where the cladding has been applied and the building’s overall fire safety measures.
Metal composite panels (MCP) are part of a cladding system on the external areas of buildings and can be a variety of colours, or they can be grey or colourless.
MCP can be different shapes and can be used in a variety of ways, such as covering a part of a wall or covering the whole wall, or as a decorative feature around windows and doors, on balconies, awnings, and signage on walls.
MCP products are sandwich-type panels, usually between 2-5mm thick, that consist of two metal outer layers and a core material. MCP includes products with outer layers of copper and zinc but the most common are products that use aluminium as the outer layer. These are referred to as aluminium composite panels (ACP).
The panel cores are made of a variety of materials, including polyethylene (PE), which may vary considerably in terms of their combustibility and ability to spread fire.
The use of MCP has become more common in the past 10 years, however, ACP has been in use as a building product since the late 1980s, so it may be present on older buildings. Common industry names for some types of ACP include ACP PE and ACP FR.
Insulated cladding systems are external wall systems comprised of bulk foam insulation that is fixed to a structural frame and then sealed, rendered and painted.
These systems are lightweight and have good thermal insulating properties because they use a thick layer of insulating foam such as polystyrene, polyurethane and polyisocyanurate.
The systems can be difficult to identify visually because they can look like rendered brick or concrete. However, tapping on the surface of these systems often produces a distinct sound such as a hollow thud, that is unlike the sound of tapping brick or concrete.