Unsafe Cladding

Definition and Technical Scope#

In the context of the UK built environment, the term "unsafe cladding" refers to cladding systems or components that do not meet contemporary fire safety performance expectations. While the phrase is frequently used in public discourse, within the technical sphere of external wall consultancy, it describes materials or assemblies that fail to satisfy current functional requirements for resistance to fire spread as defined by the Building Regulations and associated statutory guidance.

The term does not apply solely to the outer decorative rainscreen. It encompasses the entire External Wall System (EWS), including insulation, cavity barriers, sub-frames, and fixings. A system may be deemed to fall below current safety expectations not necessarily because a single component is flammable, but because the combination of materials and the method of installation—such as the presence of combustible bypasses or inadequate fire stopping—presents a risk of rapid fire spread across the building envelope.

Role in Testing and Assessment#

The identification of cladding that fails to meet safety benchmarks is typically the outcome of a structured assessment process, most notably the PAS 9980:2022 methodology. This British Standards Institution (BSI) code of practice provides a framework for competent professionals to conduct Fire Risk Appraisals of External Walls (FRAEW). Unlike previous binary assessments, this process evaluates the risk to life based on the building’s height, occupancy, and fire strategy.

During an intrusive inspection, surveyors take core samples of the building fabric to identify the material composition of the rainscreen and insulation. Common findings that lead to a categorisation of concern include:

• Metal Composite Material (MCM) with a polyethylene (PE) core.
• High-Pressure Laminate (HPL) panels used in inappropriate configurations.
• Expanded Polystyrene (EPS) or other combustible insulation without adequate mitigation.
• Missing or incorrectly installed cavity barriers that fail to prevent the "chimney effect."

External Wall Systems and Building Fabric#

The relationship between the term and the building fabric is holistic. It is a common technical misconception that "unsafe cladding" refers only to the outermost layer. In practice, the performance of the external wall is determined by how heat and flame interact with every layer of the assembly. For instance, a non-combustible A1-rated aluminium panel may still be part of a system deemed to meet safety concerns if it is installed over combustible insulation without appropriate fire breaks.

Furthermore, the mechanical stability of the system during a fire event is a critical consideration. If a cladding system is prone to delamination or melting at low temperatures, it may expose underlying combustible materials or create hazards for occupants and the fire service. Professional assessments therefore examine the integrity of the entire build-up, from the internal substrate to the external finish.

Regulatory Context in England and Wales#

The regulatory landscape regarding external wall safety has undergone significant transition since 2017. The primary legislative drivers are the Building Safety Act 2022 and the Fire Safety Act 2021. These acts clarified that the external walls of multi-occupied residential buildings fall under the scope of the Fire Safety Order (2005), requiring "Responsible Persons" to account for the risks posed by cladding.

In England, the Department for Levelling Up, Housing and Communities (DLUHC) oversees various remediation funds, such as the Building Safety Fund and the Social Sector Clarification Fund. These are designed to address cladding systems on buildings over 11 metres that are deemed to require replacement or significant mitigation. The regulatory focus remains on the "proportionality" of the response; not every building with combustible materials requires full removal, provided a competent professional determines the overall risk to life is low or can be managed through other fire safety measures.

Implications for Building Management#

For building owners, managing agents, and Right to Manage (RTM) directors, the identification of cladding that does not meet contemporary standards triggers a series of legal and operational obligations. Once a professional assessment confirms that a system is not compliant with current safety expectations, the building's Fire Risk Assessment (FRA) must be updated to reflect this.

The presence of such materials often impacts the "EWS1" (External Wall System) rating, a valuation tool developed by RICS to assist lenders in assessing the risk of a property. A rating of B2 typically indicates that remediation is required. Management teams must then navigate the complexities of procurement for remediation works, potential litigation against original developers, and applications for government funding, all while ensuring that interim safety measures—such as enhanced fire detection systems—are in place if required by the local Fire and Rescue Service.

Common Misunderstandings#

A frequent misunderstanding is the belief that "unsafe cladding" is synonymous with "illegal cladding." Many buildings were constructed using materials that were permitted under the building regulations in force at the time of installation. The retrospective application of modern safety standards means that a system can be deemed unsafe by today’s criteria without the original installation having been a breach of the law at the time.

Another common misconception is that the presence of any combustible material automatically necessitates total removal. Under PAS 9980, the emphasis has shifted toward risk-based outcomes. If a building has robust internal fire protections, multiple escape routes, and only small quantities of combustible trim, a professional may conclude that the risk is tolerable. The term is therefore relative to the specific context of the building's design and use.

Related Terminology and Performance Classes#

Understanding the technical nuances requires familiarity with the European Classification (Euroclasses) for the reaction to fire of construction products (BS EN 13501-1).

The distinction between "reaction to fire" (how a material contributes to a fire) and "fire resistance" (how long a system can withstand a fire) is also vital. The term "unsafe cladding" almost exclusively pertains to the reaction to fire and the subsequent risk of external flame spread.