Cladding types: a guide to identifying them.

Why identification matters

The fire performance of an external wall depends on the whole build-up, not just the outer face: the cladding, the insulation behind it, the cavity and its cavity barriers, the fixings and the attachments such as balconies. A non-combustible face can sit in front of combustible insulation, and a wall that looks like brick may be thin brick slips on an insulated board.

Common wall and cladding types

Type	What it usually looks like	What a FRAEW checks
Aluminium composite material (ACM)	Flat, smooth metal panels, often coloured, with folded edges	The core: polyethylene, fire-retardant or mineral-filled
High-pressure laminate (HPL)	Flat panels, often wood-effect or coloured, fixed to rails	The grade of panel, the insulation behind and the cavity barriers
Metal rainscreen	Solid aluminium, zinc or steel cassettes, or standing seam	The insulation and membranes behind, and the cavity barriers
Render on insulation	Smooth or textured render, often on blocks of flats from the 1990s onwards	Whether the insulation is mineral wool or a combustible foam
Brick slips	Looks like brickwork, but uses thin brick tiles	The carrier board, adhesive and insulation behind
Timber cladding	Boards, often on lower-rise buildings and balconies	The timber treatment, cavity and what lies behind
Terracotta and ceramic	Tiles, panels or baguettes in a rainscreen	The insulation behind and the cavity barriers
Curtain walling and spandrels	Glazed systems with opaque panels between floors	What the spandrel panels contain, and the fire-stopping at each floor
Masonry cavity walls	Traditional brick or block	The cavity insulation, cavity barriers and attachments

Balconies and attachments

PAS 9980 looks at attachments as well as the wall itself. Balconies with timber or composite decking, combustible balustrade panels, or privacy screens can add to the risk of fire spread, depending on their materials, size and position.

Why appearance can mislead

• At West Plaza, the original façade of a 1960s tower was found behind later steel cladding.
• At The Pavilion, Liverpool, there were no drawings or records, so three wall types had to be proven on site.
• At Avalon House, Portsmouth, a 1970s block with no records, every wall was proven by opening up.

How a FRAEW confirms the wall build-up

We start with the records, then inspect every wall type and attachment. Where the build-up or critical details such as cavity barriers cannot be confirmed, our in-house contracting team makes small, targeted openings and makes them good. The findings are recorded in the FRAEW report. See cladding intrusive investigations.

Frequently asked questions

Is all cladding dangerous?

No. Many wall types carry a low risk, and even where combustible materials are present, PAS 9980 assesses the risk in the context of the whole building. A FRAEW recommends what is proportionate.

Can you identify ACM from photographs?

Photographs can suggest a panel type, but they cannot confirm the core material. That needs records, testing or a sample taken during an inspection.

Does rendered insulation need checking?

Yes. Render can sit on mineral wool or on a combustible foam insulation, and the two look the same from outside. A FRAEW confirms which, usually by opening up.

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