The critical role of non-combustible materials in the modern built environment
Welcome back to our Certifix Fire Barrier series, a crucial collaboration with our trusted partners at AIM where we try to educate and refresh our audience with the key talking points around fire barriers and their importance in modern building environments.
In the UK, the landscape of fire safety has undergone a dramatic and necessary transformation, driven by tragic events and the subsequent spotlight on building materials. Our mission is to provide clarity and expert guidance on a subject that remains a source of significant concern: the combustibility of external façade panels.
It is no longer acceptable to consider a building's fire safety in isolation; the entire external wall system, from the internal substrate to the outermost cladding, must be treated as a single, interdependent safety system. We are here to answer the most critical question facing property owners today: "How vital is the fire performance of my façade, and what does the law now demand?"
This article provides a critical examination of why façade panels are considered an extreme fire risk, using UK case studies like The Cube student flat in Bolton [8] and Lakanal House [9] to illustrate failure modes. We will detail the specific combustible materials now under scrutiny, explain the dramatic changes introduced by the Building Safety Act (BSA) and the revised height limits, and underscore the severe financial and legal penalties associated with non-compliance, referencing the PAS 9980 Form and leaseholder protections.
Table of contents:
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Façade Panels are as Critical as the Substrate Itself
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Case Study 1 The Failure of Panel Material – The Cube, Bolton, Manchester (2019)
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Case Study 2 The Failure of the External Cavity – Lakanal House, London (2009)
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The Spectrum of Combustible Façades Now Under Scrutiny
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The Building Safety Act 2022 and the New Regulatory Regime
- Conclusion: Lessons Learned and the Path to Compliance
Façade Panels are as Critical as the Substrate Itself
When a fire stars externally to the building (e.g. a parked car fire or an arson attack) the façade panel forms the first form of protection for the building. Whether an external fire source, or internal fire breaking out through a window, the combustibility of the façade panel is paramount. If a façade panel is combustible it will add fuel to the fire and allow it to easily spread over the façade of the building or if it has a low melting point, it can fail quickly (e.g. in as little as 10 minutes!) at which point smoke and fire vents to the atmosphere however failure of the façade opens up the external wall cavity behind it. If this cavity is not adequately protected with cavity barriers the cavity can then act as a chimney, allowing fire, heat, and smoke to bypass internal passive fire protection measures and spread vertically and horizontally across the building with catastrophic speed.
Case Study 1: The Failure of Panel Material – The Cube, Bolton, Manchester (2019)
On a Friday evening in November 2019, a fire broke out on a fourth-floor of The Cube, a six-storey student accommodation block. Investigators later determined the cause was likely to be a discarded cigarette on a combustible balcony.
What happened next was captured in harrowing social media footage - the fire didn't stay contained, It gripped the exterior of the building and "crawled" upward with terrifying speed. Within 30 minutes, the blaze had reached the sixth floor and the roof [8]. Thanks to the swift arrival and organisation of the Fire Brigade – 130 firefighters attending the scene at it’s peak, 217 residents were evacuated and just 2 people were treated for minor injuries. A miracle given the speed of the spread.
(The Telegraph via YouTube)
Before the Bolton fire, the national focus was almost entirely on ACM (Aluminium Composite Material)—the specific type of cladding responsible for the Grenfell tragedy. The Cube fire changed that narrative overnight for two reasons:
1. The Rise of HPL (High-Pressure Laminate)
The Cube was not clad in ACM. Instead, it used High-Pressure Laminate (HPL) panels. At the time, HPL was widely considered "safer" than ACM, and the government's expert panel had previously suggested that HPL was less of a priority for remediation.
The Bolton fire proved this assumption wrong. It demonstrated that HPL, especially when combined with combustible insulation or poor cavity barriers, could facilitate rapid fire spread just as effectively as ACM. This led to a massive shift in focus, forcing building owners to reassess thousands of buildings that were previously thought to be "low risk."
2. The "18-Metre Myth"
Perhaps the most significant aspect of The Cube was its height. The building was recorded at approximately 17.8 metres tall - just a few centimetres shy of the 18-metre threshold that triggered stricter fire safety regulations at the time.
This highlighted a glaring flaw in UK legislation: fire does not respect arbitrary height measurements. The fact that a "sub-18m" building could fail so catastrophically led directly to the government lowering the threshold for the combustible materials ban to 11 metres and the eventual introduction of the Building Safety Act 2022 [1.4].
Case Study 2: The Failure of the External Cavity – Lakanal House, London (2009)
(ITN news coverage)
The fire at Lakanal House on July 3rd 2009, is often described as the "missed warning" that could have prevented the Grenfell Tower tragedy. Occurring eight years before Grenfell, this South London blaze exposed deep-seated flaws in the UK’s approach to high-rise refurbishments, fire safety inspections, and the materials used in facade systems.
The fire began in a flat on the ninth floor of the 14-storey block in Camberwell, caused by a faulty television. While the initial fire was relatively small, it did not stay contained. It breached the building's exterior and spread with unexpected speed—both upward to the top floors and downward to lower levels. The fire spread to the 11th floor in less than 20 minutes, trapping residents who had been told to "stay put." Whilst over 100 people were evacuated, 6 people tragically lost their lives including 3 children and 3 women [9].
Lakanal House was a turning point for how the industry viewed external wall systems. The inquest into the deaths highlighted that the building had been "made unsafe" by the very refurbishments intended to improve it.
1. The "Downgrade" in Fire Resistance
During a refurbishment in 2006–2007, the original window sets (which featured fire-resistant asbestos-based panels) were replaced. The new units used composite panels made of a polyester-coated aluminium skin with a combustible core.
The inquest found that these new panels were significantly less fire-resistant than the materials they replaced. They burned through in less than five minutes, allowing the fire to bypass the building's internal compartmentation and re-enter flats on higher floors. [4]
2. The Failure of "Class 0"
At the time, the panels were marketed as having a "Class 0" rating. This was a British standard that measured the spread of flame across a surface but did not adequately account for how the material behaved when exposed to intense, sustained heat or whether it was actually combustible. [10]
The Lakanal House fire proved that "Class 0" was an insufficient safety benchmark for high-rise buildings. Despite this, the regulatory changes requested by the coroner were largely delayed or ignored by the government, a failure that would be cited heavily during the later Grenfell Tower Inquiry.
For Certifix and AIM, this case underscores a fundamental principle: a fire-safe façade system requires both non-combustible panels and correctly installed, compliant passive fire protection within the entire external wall cavity. If the cavity is breached by a melting or burning panel, the internal fire barrier systems are compromised.
The Spectrum of Combustible Façades Now Under Scrutiny
While ACM (specifically metal composite materials with an unmodified combustible polyethylene core) remains the most notorious example, the regulatory spotlight has broadened significantly:
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Any Combustible Material |
Fire Risk Concern |
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High Pressure Laminates (HPL) |
Ignites and sustains fire, as seen in The Cube. |
|
Aluminium & Zinc Composite Panels |
Aluminium and Zinc have a low melting points, causing the external face to fail, exposing the potentially combustible core and the cavity behind. |
|
Timber Cladding & Balconies |
Used on balconies and external walls, providing an easy vertical and horizontal fire path. |
|
Unmodified Polyethylene (PE) Core MCMs |
Now completely banned on all buildings, regardless of height, due to extreme combustibility [2.3]. |
The Building Safety Act 2022 and the New Regulatory Regime
Following the lessons from fire related tragedies, the UK Government introduced comprehensive legislative reforms. The Building Safety Act 2022 (BSA) represents a fundamental shift towards accountability and safety.
1. Stricter Height Limits and Ban Extension
The initial ban on combustible materials in external walls applied to high-rise residential buildings (HRBs) over 18m. This has been consistently reinforced and expanded [3]:
- 18m+ Buildings (High-Rise): The use of combustible materials (anything below A2-s1, d0) is banned in the external walls of new buildings of at least 18 metres containing one or more dwellings, hospitals, care homes, and student accommodation [1.1]. The ban has also been extended to include new hotels, hostels, and boarding houses over 18m [1.3].
- 11m+ Buildings (Mid-Rise): New guidance in Approved Document B now requires external wall surfaces and insulation on new residential buildings between 11m and 18m to achieve a classification of at least A2-s1, d0 [1.5].
2. The Dutyholder Regime
The BSA 2022 defines new roles and responsibilities to ensure accountability throughout a building's lifecycle [2]:
- Dutyholders (Design & Construction): These include the Client, Principal Designer, and Principal Contractor, who must demonstrate competence and actively plan, manage, and monitor work to ensure compliance with all Building Regulations [5].
- Accountable Person (Occupation): For occupied Higher-Risk Buildings (HRBs—generally 18m+/7 storeys with 2+ residential units), the Accountable Person (AP) and Principal Accountable Person (PAP) are legally responsible for managing building safety risks and maintaining a comprehensive 'Golden Thread' of information [6].
The Financial Imperative: Zero Value and Uninsurability
The presence of non-compliant, combustible external wall systems has triggered a financial crisis in the UK property market according to recent reports [11].
- Mortgage and Valuation: Buildings with combustible ACM or HPL may be deemed un-mortgageable or receive a zero valuation from surveyors. [12]
- The EWS1 Form: The Royal Institution of Chartered Surveyors (RICS) EWS1 Form (External Wall System Fire Review) was introduced to facilitate the valuation of flats in multi-storey residential buildings over 18 metres. A rating that indicates significant combustible materials or inadequate fire breaks (e.g., a Euroclass B rating) can halt sales and refinancings until remediation is complete [7].
- PAS 9980. The British Standards Institute (BSI) have worked with industry experts to create a robust methodology for assessing the safety of external walls in High Risk Buildings (HRB’s). Not every tall building requires a formal PAS 9980 assessment (masonry external wall constructions for example) but when there is any doubt as to the performance of the external wall in a fire situation, PAS 9980 allows for the risks to be suitably assessed by a competent person and mitigating measures put in place.
The Building Safety Act 2022 includes leaseholder protections, specifically ensuring that leaseholders in buildings over 11 metres are not required to pay for the removal of unsafe cladding systems [1.6]. This legal burden, however, shifts the remediation cost squarely onto developers or building owners, further highlighting the financial liability of non-compliance.
Conclusion: Lessons Learned and the Path to Compliance
The fires at Lakanal House and The Cube serve as stark reminders that building safety is an evolving discipline, one where past oversights have paved the way for today’s more rigorous standards. These incidents demonstrated that fire does not respect arbitrary height limits and that "Class 0" ratings provided a false sense of security that led to catastrophic outcomes [8, 9]. By proving that materials like HPL can be just as hazardous as ACM under certain conditions, these events forced the UK to abandon the "18-metre myth" and adopt the more stringent 11-metre threshold we see today [1.4, 7]. We have moved into an era where the entire external wall system of High Risk Buildings is under the microscope, and the "Golden Thread" of information ensures that every aspect of the buildings fire safety is accounted for throughout the building's lifecycle [6] which includes façade panels and cavity barriers.
For property owners and managers in 2026, the stakes are no longer just about meeting minimum safety requirements; they are about protecting lives and maintaining the financial viability of their assets. Responsible persons need to ensure that any maintenance, upgrades and changes made to the building are only undertaken by competent people with the necessary Skills, Knowledge, Experience and Behaviour (SKEB) to complete the task. Fire safety measures and systems within the building must be routinely inspected and inspections documented. With surveyors frequently issuing "nil valuations" for buildings that cannot provide clear evidence of non-combustible facades, the risk of inaction is a complete loss of property liquidity [12]. The EWS1 process (or PAS 9980) and the Building Safety Act have made transparency a legal and economic necessity [6]. At Certifix and AIM, we welcome this approach.
References
[1] The Building (Amendment) Regulations 2018 (SI 2018/1230) https://www.legislation.gov.uk/uksi/2018/1230/pdfs/uksiem_20181230_en_002.pdf
[1.1] Referenced in search result snippet detailing the initial ban scope.
[1.3] Referenced in search result snippet detailing the extension of the ban to hotels/hostels over 18m.
[1.4] Referenced in search result snippet detailing the guidance for buildings 11-18m.
[1.5] Referenced in search result snippet detailing the A2-s1, d0 requirements for 11m+ external wall surfaces.
[1.6] Referenced in search result snippet detailing leaseholder protections for cladding costs in 11m+ buildings.
[2] Dutyholder Regime during design and construction (Taylor Wessing) https://www.taylorwessing.com/en/insights-and-events/insights/2024/04/uc-dutyholder-regime-during-design-and-construction
[3] Combustible materials: New regulations extend ban (Taylor Wessing) https://www.taylorwessing.com/en/insights-and-events/insights/2022/06/combustible-materials-new-regulations-extend-ban
[4] Lakanal House: Response to Coroner's Recommendations https://www.gov.uk/government/publications/lakanal-house-response-to-coroners-recommendations
[5] Grenfell Tower Inquiry Phase 1 Report – Volume 3 https://www.gov.uk/government/publications/grenfell-tower-inquiry-phase-1-report-government-response
[6] The Building Safety Act 2022 (Full Text) https://www.legislation.gov.uk/ukpga/2022/30/contents
[7] RICS Professional Standard: Valuation of multi-storey residential buildings with cladding https://www.rics.org/profession-standards/rics-standards-and-guidance/sector-standards/valuation-standards/valuation-of-properties-in-multi-storey-multi-occupancy-residential-buildings-with-cladding
[8] The Cube, Bolton: Major Incident News Report https://www.bbc.co.uk/news/uk-england-manchester-53597167
[9] Lakanal House fire deaths: Council fined for safety breaches https://www.bbc.co.uk/news/uk-england-london-39116172
[10] A Critical Appraisal of the UK’s Regulatory Regime for Combustible Façades https://doi.org/10.1007/s10694-020-00993-z
[11] London Assembly: Cladding Crisis and its Impact on Londoners https://meetings.london.gov.uk/documents/s88568/Appendix%201%20London%20Assembly%20report%20-%20Cladding%20Crisis%20-%20January%202021.pdf
[12] Housing Ombudsman Spotlight Report on Cladding https://www.housing-ombudsman.org.uk/app/uploads/2021/03/Spotlight-report-on-cladding.pdf
