RICS Tightens EWS1 Rules: What Leaseholder-Landlords With Flats Must Do Before the Mortgage Market Closes

The Royal Institution of Chartered Surveyors has updated its guidance on EWS1 — the External Wall System fire safety assessment form introduced after Grenfell — and the consequences for private landlords who hold leasehold flats are more immediate than most commentary has acknowledged. This is not a clarification of existing rules. It is a tightening of the conditions under which a valid EWS1 sign-off can be used to support a mortgage valuation, and it arrives at a moment when the leaseholder-landlord population is already carrying disproportionate exposure to building safety costs, stalled sales, and lengthening transaction timelines.

The EWS1 system was always imperfect. It emerged as an emergency measure in 2019 to unblock a mortgage market that had seized after lenders began refusing to lend on any flat above 18 metres without documented evidence of cladding safety. The form itself is deceptively simple: a qualified professional signs off that external wall systems either present no elevated risk, or that remediation has been carried out or is underway. What made it contentious from the outset was the question of who counts as qualified, who carries the professional indemnity insurance to back the assessment, and how long a sign-off remains valid before a building's circumstances change. RICS is now answering those questions more precisely, and the answers are not landlord-friendly.

Does Your Existing EWS1 Sign-Off Still Hold Under the New Criteria?

The central change concerns the competency requirements for assessors and the conditions under which a previously issued EWS1 form can still be relied upon by a lender's valuer. Under the tightened guidance, assessors must now meet a more explicitly defined competency framework, and forms signed by professionals who do not satisfy that framework, or who no longer carry adequate professional indemnity cover, may be treated as invalid by lenders even if the physical condition of the building has not changed. This matters because a significant number of EWS1 assessments were conducted in the period between 2020 and 2022 by professionals whose qualifications sat at the edge of the acceptable range. Landlords who obtained a sign-off during that window and have been relying on it to maintain mortgage access or to facilitate a sale are now exposed to the possibility that their valuer will not accept the form.

The practical consequence of an invalid or unacceptable EWS1 form is a blocked valuation, which in the current environment means either an unmortgageable property or a mortgage retention that makes a transaction non-viable. The Leasehold Advisory Service data already shows leasehold transactions averaging 155 days to exchange, a figure that includes buildings where the EWS1 process is still ongoing. Landlords who assumed their building had cleared this hurdle should not assume that remains the case without verifying that the assessor named on their form still meets RICS criteria and that their insurer has confirmed ongoing cover. Neither of those checks is automatic, and neither will be flagged proactively by the freeholder or managing agent.

There is a compounding problem for landlords who hold flats in buildings under 18 metres. The mortgage market has never applied EWS1 requirements consistently across all height categories, and many lenders developed their own internal criteria that extended the requirement below the threshold RICS originally contemplated. The new guidance does not fully resolve that inconsistency. It tightens the competency and validity framework for forms that are used, but it does not legislate for which buildings require a form at all. Individual lender criteria therefore continue to diverge, meaning a flat that does not technically require an EWS1 assessment under RICS guidance may still be effectively unmortgageable with certain lenders who have imposed their own requirements. Landlords remortgaging this year, particularly portfolio landlords whose buy-to-let financing is already under pressure from higher base rates, face the realistic prospect of discovering mid-process that their lender requires documentation their building has never produced.

Who Bears the Cost When an Assessment Must Be Repeated or Upgraded?

The cost question is the one most landlords are least prepared for, and the legal position is more ambiguous than it should be at this stage in the post-Grenfell reform process. EWS1 assessments are building-level, not unit-level. The cost of commissioning a new or updated assessment falls, in principle, on the freeholder or the residents' management company, not on individual leaseholders. In practice, those costs are frequently passed through service charges, and the mechanism by which a freeholder can allocate EWS1 reassessment costs to leaseholders remains a live area of legal dispute. The Building Safety Act 2022 introduced protections for qualifying leaseholders against certain building safety costs, but those protections have conditions and thresholds that do not cover every scenario, and the definition of a qualifying leaseholder excludes landlords who own more than three properties nationally at the time the relevant remediation obligation arose.

That exclusion is the critical point for portfolio landlords. If you hold more than three leasehold properties, you are not a qualifying leaseholder under the Act's protective provisions, and you can be required to contribute to EWS1 reassessment costs through the service charge without the statutory cap that protects owner-occupiers and smaller landlords. The government's rationale was that larger landlords are commercial actors who should bear proportionate costs. The practical effect is that a landlord with four flats in different buildings, none of which they manage, has fewer statutory protections than a landlord with two, despite the fact that neither has control over the buildings in question. Legal advice from specialist leasehold solicitors has consistently identified this threshold as an area where landlords significantly underestimate their exposure.

The interaction with remortgaging is where the financial pressure becomes acute. Portfolio landlords driving the current buy-to-let remortgage push, as the market data confirms they are, will increasingly encounter lenders whose surveyors flag EWS1 concerns during the valuation process. If the existing form is rejected, the lender will typically require a new assessment before proceeding. The landlord cannot commission that assessment unilaterally; they must engage the freeholder, who may be unresponsive, in dispute with their own insurer, or managing a queue of buildings with competing demands on qualified assessors. The timelines involved are not weeks. Assessors with the right qualifications and adequate professional indemnity cover remain in short supply, a structural problem that RICS tightening competency criteria will not improve in the near term.

The forward position is one of increasing divergence between landlords who proactively verified their EWS1 position in 2024 and 2025 and those who did not. Lenders are refining their internal policies in response to the updated RICS guidance, and the direction of travel is toward stricter reliance on current, verifiable assessments rather than historical forms. Landlords who have not reviewed their EWS1 documentation in the last twelve months, confirmed the assessor's ongoing qualification status, and checked their building's position under the Building Safety Act's qualifying leaseholder threshold should treat all of those as open risk items rather than resolved ones. The mortgage market will not wait for those checks to be completed before declining to lend.