Fire Safety · Mandatory · Construction

Cladding and External Wall System Record

A record of the external wall system including cladding materials and fire performance test data.

Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. BSA 2022 / Building Regs B remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.

Legal basis	Building Safety Act 2022 (BSA 2022) + Building Regulations Approved Document B (Fire Safety)
Cross-reference	K8 — Cladding / Facade Specification Record (design-stage specification and substitution control)
Over 18 m requirement	Materials in the external wall of a building over 18 m must achieve limited combustibility — Euroclass A2-s1,d0 or better under BS EN 13501-1
Golden thread	Cladding and external wall records form a critical part of the golden thread of building information required for all higher-risk buildings (HRBs) under BSA 2022
Notifiable change	Any substitution of cladding materials on a higher-risk building is a notifiable change under BSA 2022 and must be reported to the Building Safety Regulator before work proceeds

1. Cladding / External Wall System Record

The Grenfell Tower fire on 14 June 2017 killed 72 people. The fire spread with catastrophic speed because the external wall system — the cladding, insulation, and cavity barriers — contained combustible materials that allowed flame to travel rapidly up the exterior of the building. The lessons of Grenfell are now applied to every higher-risk building through the Building Safety Act 2022, which requires a comprehensive, accurate, and permanently maintained record of every component of the external wall system.

For buildings over 18 metres in height (or over 7 storeys), Approved Document B requires that materials used in the external wall achieve limited combustibility, classified as Euroclass A2-s1,d0 or better under BS EN 13501-1. This effectively prohibits the use of combustible cladding panels, combustible insulation, and combustible filler materials in the external wall of tall buildings. The cladding / external wall record is the documented evidence that these requirements have been met.

For existing buildings, PAS 9980:2022 provides a methodology for assessing the fire risk posed by external wall systems. It is used by competent professionals to evaluate whether remediation is required and, if so, what form that remediation should take. The EWS1 (External Wall System Fire Review) form is the standardised output of this assessment process and is used by lenders and valuers to determine whether a building is mortgageable.

The cladding / external wall record forms a critical element of the golden thread of building information for higher-risk buildings. The golden thread is the single, authoritative source of information about a building's design, construction, and ongoing management. It must be accurate, accessible, and kept up to date throughout the life of the building. The Building Safety Regulator can require the production of golden thread information at any time.

Any cladding substitution on an HRB is a notifiable change

Under the Building Safety Act 2022, any change to the specification of external wall materials on a higher-risk building — including substitution of cladding panels, insulation, cavity barriers, fixings, or membranes — is a notifiable change. The change must be reported to the Building Safety Regulator before work proceeds, and the Regulator has the power to require additional information, impose conditions, or refuse the change. Proceeding with a material substitution without notification is a criminal offence. This requirement applies regardless of whether the substitute material is claimed to be equivalent to the original specification.

2. Key Elements

The following table sets out the key elements that a cladding / external wall system record must capture. Each element must be evidenced with supporting documentation and maintained as part of the golden thread.

Element	Detail
Building reference	Unique building identifier, address, number of storeys, height in metres, building use (residential, mixed-use), and whether the building is classified as a higher-risk building under BSA 2022.
Facade zone	The external wall is divided into defined facade zones. Each zone is identified on the elevation drawings and may have a different cladding specification, orientation, or exposure condition. Records are maintained per zone to ensure traceability.
Cladding layer specification	Full specification of every layer in the external wall build-up for each facade zone: external cladding panel (manufacturer, product, thickness, Euroclass rating), insulation (manufacturer, product, thickness, Euroclass rating), membranes, sheathing boards, cavity dimensions, and fixing system.
Fire test evidence	Copies of fire classification reports to BS EN 13501-1 for each material, and where applicable, large-scale fire test reports to BS 8414 with classification to BR 135. Evidence must be product-specific — generic classifications are not acceptable.
As-built confirmation	Photographic and written confirmation that the materials installed match the approved specification. This includes delivery tickets, batch numbers, installation photographs at each layer, and a signed confirmation from the installer that no substitutions have been made.
Cavity barrier inspections	Record of cavity barrier installation at every required location (around openings, at compartment lines, at the top of the wall, and at maximum 20 m horizontal intervals). Includes inspection photographs, installer sign-off, and confirmation that barriers are correctly fitted with no gaps.
Installer	Name and competence details of the cladding installer, including relevant accreditations (e.g. CWCT, CSCS, FIS), evidence of training on the specific system being installed, and confirmation of adequate professional indemnity insurance.
EWS1 form	For existing buildings undergoing assessment, the EWS1 (External Wall System Fire Review) form records the outcome of the fire risk appraisal carried out in accordance with PAS 9980:2022. The form is completed by a competent professional (RICS-registered valuer or chartered fire engineer) and confirms the fire risk rating of the external wall system.

3. Common Mistakes

See K8 (Cladding / Facade Specification Record) for full common mistakes

The cladding / external wall system record and the K8 cladding / facade specification record are closely related documents. The K8 governs the design-stage specification and substitution control process, while this record captures the as-built evidence. The most common and serious mistakes — including unauthorised material substitutions, missing fire test evidence, incomplete cavity barrier records, and failure to notify the Building Safety Regulator of changes — are covered in detail in the K8 guide. Refer to K8 for the full list of common mistakes and how to avoid them.

4. Frequently Asked Questions

What is PAS 9980:2022?▾

PAS 9980:2022 is a publicly available specification published by BSI that provides a code of practice for the fire risk appraisal of external wall construction and cladding of existing blocks of flats. It was developed in response to the Grenfell Tower fire and gives competent professionals a structured methodology for assessing the fire risk posed by external wall systems. The appraisal considers the specific materials present, the building height and geometry, the presence and condition of cavity barriers, the fire strategy of the building, and other relevant factors. The outcome of a PAS 9980 appraisal informs decisions about whether remediation is needed and, if so, what level of intervention is proportionate. PAS 9980 replaced the earlier EWS process that applied a more binary pass/fail approach and caused significant issues for leaseholders attempting to sell or remortgage their properties.

What is the EWS1 form?▾

The EWS1 (External Wall System Fire Review) form is a standardised document used to record the outcome of a fire risk appraisal of a building's external wall system. It was introduced by the Royal Institution of Chartered Surveyors (RICS), UK Finance, the Building Societies Association, and other industry bodies to provide a consistent format for reporting external wall assessments to lenders and valuers. The form is completed by a competent professional — either a chartered fire engineer or an RICS-registered valuer with appropriate qualifications. The form records whether combustible materials are present in the external wall, and if so, the assessed level of risk. Lenders use the EWS1 form to determine whether a property in the building is mortgageable. A building that receives a rating indicating unacceptable risk may require remediation before individual flats within it can be sold or remortgaged.

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