UK Cladding EWS1 Cost and Mortgageability

Enter the building height in metres measured from ground level to the top of the highest storey. Height determines which regulatory threshold applies: under 11 m (generally outside EWS1 scope), 11–18 m (EWS1 required by most lenders if combustible materials are present), over 18 m (highest level of scrutiny and building safety requirements).

Choose the cladding type that applies to the building. Aluminium composite material (ACM) with combustible polyethylene core — the type used at Grenfell Tower — is the highest risk. High-pressure laminate (HPL) panels are also a concern. Render systems and other types carry different profiles. If you are unsure, the EWS1 or PAS 9980 report will specify the materials assessed.

Enter the total number of flats in the building. Remediation costs are typically shared across leaseholders (though the Building Safety Act limits or eliminates this in qualifying cases). Enter your flat's current value — this is used to assess the London or high-value threshold for the leaseholder cost cap.

Select whether you hold a qualifying lease under the Building Safety Act. A qualifying leaseholder is broadly someone who owns the property as their main home (or has owned it as such), has not owned more than three UK properties at any one time, and is not the developer or a connected person. If you qualify, the Act caps or eliminates many remediation costs.

The tool shows an estimated gross remediation cost range based on building characteristics and a simplified share calculation. Qualifying leaseholders are shown their estimated capped exposure. Non-qualifying leaseholders may see a higher liability estimate. These are estimates — the actual cost depends on the specific works required after a full PAS 9980 assessment.

The output gives an indicative mortgageability risk level based on the inputs. A red signal means many lenders may currently decline to lend. Amber means lending may be possible with appropriate evidence such as a satisfactory EWS1 form. Green means the building characteristics fall outside the main EWS1 scope, though individual lenders may still have additional requirements.

Before buying, selling, remortgaging or estimating costs further, the tool lists the key documents you should request: EWS1 form, PAS 9980 assessment, fire risk assessment, freeholder correspondence with the Building Safety Fund, and any signed Developer Remediation Contract.

An EWS1 form (External Wall System 1) is a standardised certificate issued by a qualified professional (a registered fire engineer) confirming whether the external wall system of a building is safe, needs remediation, or is in the highest-risk category. It has a simple A1/A2/B1/B2 rating. A1 means no concerns; B2 means immediate action is likely required.

PAS 9980 is a British Standard published in 2022 that provides a more detailed methodology for assessing fire risk in the external walls of existing residential buildings. It produces a fire risk appraisal of external walls (FRAEW) report. Where a PAS 9980 assessment has been carried out, it effectively supersedes the need for a standalone EWS1 in many cases. Some lenders accept either; others have specific requirements.

The Building Safety Act 2022 introduced statutory protections for qualifying leaseholders in buildings over 11 metres. In summary: if the developer of the building can be identified and located, they are responsible for the full cost of remediation with no liability to leaseholders. If the freeholder or building owner has a net worth above £2 million, they must pay without passing costs to qualifying leaseholders. If neither applies, qualifying leaseholders face a cap that depends on the property value and whether it is in London.

The cap for qualifying leaseholders outside London is set at a percentage of the property's value (subject to an absolute maximum). In London the cap is higher. Non-qualifying leaseholders (those who own additional properties or are connected to the developer) may face the full uncapped share.

Since the Grenfell Tower fire in 2017, many mortgage lenders have applied enhanced scrutiny to flats in buildings with combustible cladding. The UK Finance and Building Societies Association have produced guidance for lenders, but individual lender policies vary. Some lenders will lend on buildings with a satisfactory EWS1 or PAS 9980 report; others remain cautious about certain building types regardless of documentation.

The situation is improving as buildings are remediated and more EWS1 forms are issued. However, buyers and sellers of affected properties should check current lender policy before agreeing terms and should factor potential delays into their transaction timeline.