Identifying cladding on London's residential buildings
Understanding what type of cladding is on your building is the essential first step in assessing fire safety risk. London's residential stock includes a wide range of cladding systems, from aluminium composite panels to rendered insulation systems. A facade investigation can confirm the materials present and inform the next steps.
ACM (Aluminium Composite Material)
ACM panels are among the most widely discussed cladding types following the Grenfell Tower fire. They consist of two thin aluminium sheets bonded to a core. Panels with a polyethylene (PE) core are highly combustible. FR (fire-retardant) and A2 (mineral) cores offer progressively better fire performance. ACM is commonly found on buildings constructed or refurbished between the mid-1990s and late 2010s, particularly on taller residential blocks.
HPL (High Pressure Laminate)
HPL panels are made from layers of kraft paper and resin compressed under heat and pressure. They are lightweight, durable and available in a wide range of finishes. However, many HPL products are combustible and have been subject to remediation requirements where used on residential buildings above 18 metres. HPL can be difficult to distinguish from other panel types without close inspection or access to construction records.
Render and ETICS systems
External thermal insulation composite systems (ETICS) involve insulation boards fixed to the external wall and covered with a render finish. The fire risk depends primarily on the insulation material: expanded polystyrene (EPS) is combustible, while mineral wool and phenolic foam offer better fire performance. Render systems are extremely common on London buildings, from post-war tower blocks to modern developments.
Brick slip and terracotta
Brick slip systems use thin sections of brick or clay fixed to a carrier board or track system on the external wall. Terracotta rainscreen cladding uses hollow clay blocks in a ventilated rainscreen configuration. While the facing materials themselves are non-combustible, the fire risk relates to the insulation, cavity barriers and overall wall configuration. A cladding remediation assessment considers the entire wall system, not just the visible face.
How cladding identification is confirmed in practice
The visible outer face is only one part of an external wall system. A panel that looks like metal, render, brick slip or laminate may sit over combustible insulation, missing cavity barriers, altered fire-stopping or a support system that changes the risk profile. That is why identification starts with records and ends with evidence, not guesswork from street level.
A desktop review usually checks planning drawings, O&M manuals, fire strategy documents, previous EWS1 forms, building control records and any historic product data. The site inspection then confirms what is actually present: panel layout, fixing zones, cavity lines, balcony junctions, service penetrations, roof interfaces and the relationship between the external wall and internal compartmentation.
Where the records are incomplete, intrusive opening-up may be needed. The aim is to confirm the material build-up, not to remove more fabric than necessary. Photographs, sample locations and reinstatement notes should be recorded clearly so the findings can support a FRAEW, remediation scope, funding submission or leaseholder communication without repeating the same investigation later.
Do not rely on appearance alone
ACM, HPL, metal rainscreen, render carrier boards and brick slip systems can look similar once installed, especially after repainting or later facade works.
Check the whole wall
Risk depends on insulation, cavities, barriers, fixings, openings and management measures as well as the cladding panel itself.
Keep an evidence trail
Clear records help accountable persons, managing agents and freeholders explain what was inspected, what was found and why the next step is proportionate.
Frequently asked questions
How can I tell what type of cladding is on my building?
Visual inspection alone can be unreliable. A professional facade investigation reviews construction records, inspects the wall visually and, where necessary, carries out intrusive investigation to confirm the materials present.
Is ACM cladding always dangerous?
No. The fire risk depends on the core material. PE cores are combustible, FR cores have reduced combustibility, and A2 mineral cores are considered low risk. A FRAEW assesses the risk in context.
What is the difference between ACM and HPL cladding?
ACM has two aluminium sheets bonded to a core. HPL is compressed layers of kraft paper and resin. Both can be combustible depending on composition. The fire behaviour differs and is assessed through testing and the FRAEW process.
Does my building need cladding remediation?
It depends on the cladding system, configuration, building height and overall fire risk. A FRAEW under PAS 9980 determines whether remediation is required. Not all combustible cladding needs full removal.
How we can help
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Savas Bulduk
BSc (Hons) MRICS, Director & Chartered Building Surveyor.
Writes on Building surveying, Fire safety and facade, External wall systems, Technical due diligence, Contract administration. See the full team profile.