How EWS1 Surveys Affect Insurance and Mortgage Approvals

In this article, we explain how EWS1 surveys affect building insurance and mortgage approvals, how the system works, who it applies to, and what you need to do if you're buying, selling, or remortgaging a flat in a block affected by these rules.

Since the introduction of EWS1 forms in 2019, leaseholders and property professionals have had to navigate a new layer of complexity in the buying, selling, and insuring of flats in multi-storey buildings. Initially designed to address concerns around combustible cladding, the EWS1 process has now become central to mortgage approvals and building insurance decisions across the UK.

What Is an EWS1 Survey?

An EWS1 survey (External Wall System 1) is an assessment of a building’s external wall system to determine whether it contains combustible materials. It is typically required when buying, selling or remortgaging flats in residential buildings over 11 metres (roughly 4–5 storeys), although lenders may request it for shorter buildings depending on the construction.

The survey leads to the production of an EWS1 form, which is signed by a suitably qualified professional and classifies the wall system as either:

Option A: External wall materials are unlikely to be combustible, or risks are low.

Option B: Combustible materials are present but risks have been mitigated and managed.

Only professionals with recognised qualifications and fire safety experience (e.g., Chartered Engineers via IFE, RICS-qualified surveyors, or CABE-accredited assessors) are authorised to complete the form.

Why EWS1 Matters for Mortgage Approvals

Since the Grenfell Tower tragedy, lenders have become more cautious when dealing with flats in blocks with any form of external cladding. Many mortgage providers now require a valid EWS1 form to confirm that the building does not pose a fire safety risk.

Here’s how an EWS1 survey affects mortgage approval:

1. Lender Confidence

Lenders want to reduce risk. If a flat is in a block with potential fire safety issues, they may consider the property unmortgageable without an EWS1 form showing a satisfactory result. A completed EWS1 form gives underwriters confidence that a professional has assessed the risk and found it manageable or negligible.

2. Property Valuation

Surveyors acting on behalf of mortgage lenders may refuse to provide a valuation without seeing an EWS1 form. This effectively freezes the transaction. Even if a buyer has a mortgage offer in principle, the process can grind to a halt until the building is assessed.

3. Lender Policy Differences

Not all lenders follow the same criteria. Some major high-street banks insist on an EWS1 form for any building over 11m, while others may assess on a case-by-case basis. Where the building’s wall system is non-standard (e.g., timber cladding, render with EPS insulation), lenders are more likely to require EWS1 documentation.

How EWS1 Surveys Affect Building Insurance

Insurers use EWS1 surveys to assess their exposure to risk. The materials used in external walls significantly affect how a fire spreads and how a building can be evacuated safely. This has a direct impact on premiums, excesses, and whether an insurer will provide cover at all.

1. Premium Pricing

Buildings without a valid EWS1 form — or with one showing that combustible materials are present — often face steep increases in insurance premiums. In some cases, insurance costs have multiplied several times over due to uncertainty or adverse survey findings.

2. Refusal of Cover

Some insurers refuse to cover buildings that haven’t undergone an EWS1 assessment. If the building is found to have dangerous cladding or insufficient fire breaks, insurers may deem it uninsurable until remedial work is done.

3. Policy Terms and Excesses

Even where cover is available, insurers may impose strict conditions:

Increased excess on fire claims

Compulsory fire watches or evacuation plans

Time-limited cover pending remediation

These limitations often translate into higher service charges for leaseholders.

Buildings That Require EWS1 Forms

While the rules have evolved since 2020, the current approach focuses on height and material risk:

Above 18m (typically 6 storeys or more): EWS1 required unless the building is proven to have a safe wall system.

11m–18m: EWS1 required in some cases, especially if there are combustible materials (e.g., timber cladding, balconies).

Below 11m: Not usually required — but some lenders still request it.

Guidance from RICS and government supports a risk-based approach, meaning the presence of combustible material (not height alone) determines the need for an EWS1 assessment.

Who Can Complete an EWS1 Form?

Not just anyone can complete an EWS1 form. Only professionals with specific qualifications and competence in fire safety are authorised. These typically include:

Chartered Building Surveyors via RICS

Chartered Engineers (CEng) or Incorporated Engineers (IEng) registered with the Institution of Fire Engineers (IFE)

CABE-accredited professionals with proven fire safety competence

Anstey Horne has the largest number of chartered surveyors who have passed the RICS EWS1 Assessment Training Programme and are qualified to complete EWS1 forms in line with Option A and Option B assessments.

What Happens If the Building Fails the EWS1 Survey?

If an EWS1 survey identifies combustible materials and inadequate risk mitigation, the form will return an Option B1 or B2 result, indicating a need for remediation.

The consequences include:

Delay or failure of mortgage approval

Higher insurance premiums

Stigma affecting market value

Legal implications for developers or freeholders

Once remediation works are completed - such as replacing unsafe cladding or installing fire barriers - the building can be reassessed and a new EWS1 form issued.

How Anstey Horne Can Help

Anstey Horne is a trusted name in building safety and façade assessment. Our qualified team includes RICS and IFE professionals who can undertake:

Desktop risk reviews

On-site cladding inspections

EWS1 assessments and forms

Advice on remediation strategy

Support for freeholders and leaseholders

We have completed assessments on hundreds of buildings across the UK, from complex high-rise towers to lower-rise developments with combustible balconies.

FAQs: How EWS1 Surveys Affect Insurance and Mortgage Approvals

What is the difference between EWS1 and a fire risk assessment (FRA)?

An EWS1 survey specifically assesses the fire risk posed by the building’s external wall system. A fire risk assessment is a broader review of internal and external safety measures. Both are important, but lenders and insurers often focus on EWS1.

Can a flat be sold without an EWS1 form?

Technically yes, but practically no. Most lenders won’t issue a mortgage without a valid EWS1 if the building is deemed to need one. As a result, most sales fall through unless a compliant form is available.

Is an EWS1 form needed for buildings without cladding?

Not always — if there is no cladding and the walls are traditional masonry, timber, or other non-combustible materials, a qualified assessor can confirm this under Option A, which may speed up the process.

How long is an EWS1 form valid for?

EWS1 forms are valid for five years unless significant changes are made to the external wall system. However, if new risks are identified or building regulations change, reassessment may be required.

Who is responsible for obtaining the EWS1 survey?

Usually the building owner or managing agent arranges the survey. However, leaseholders often initiate the process if they need it to sell or remortgage. The cost is typically shared among leaseholders.

Can leaseholders challenge the findings of an EWS1 assessment?

Yes, but only by commissioning a second opinion from another suitably qualified fire professional. Lenders may accept a more recent or revised form if remediation work has been completed.

Final Thoughts - How EWS1 Surveys Affect Insurance and Mortgage Approvals

The EWS1 system is a critical part of the post-Grenfell landscape for anyone involved in residential flats. Whether you’re buying, selling, insuring, or managing a building, understanding how EWS1 surveys affect building insurance and mortgage approvals is essential.

At Anstey Horne, we help clients across the UK navigate this evolving framework with clear advice and professional expertise. Contact our team to arrange an assessment or find out if your building needs an EWS1 form.

Need Help with an EWS1 Form or Fire Risk Assessment?

We deliver EWS1 assessments across the UK with speed, precision, and professionalism. Our team is:

Registered with Royal Institution of Chartered Surveyors, Institution of Fire Engineers, BAFE Fire Safety Register, Fire Industry Association and the Chartered Association of Building Engineers

Fully qualified to complete both Category A and B assessments

Focused on delivering lender-acceptable, clear, and timely reports

Whether your building is six storeys or twenty, our experts offer comprehensive reports, risk classification, and actionable recommendations.

Contact us today to book a survey or get advice on whether your building qualifies.

With offices in London, Birmingham , Manchester, Bristol, Brighton, Norwich & Plymouth we provide EWS1 certificates and undertake Fire Risk Assessments all around the UK.

For more information on how EWS1 Surveys affect insurance and mortgage approvals or any other aspect of this service see the collection of articles in our blog.

To commission an EWS1 Survey or a Fire Risk Assessment please call our Enquiry line on 020 4534 3130.

To book a call back from a member of the Fire team, please fill in our Contact Us form.

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