EWS1 ratings explained: A1, A2, A3, B1 and B2.

Option A or Option B

The first question the signatory answers is what the external wall is made of. Option A applies where the external wall materials are unlikely to support combustion. Option B applies where combustible materials are present in the external wall. Within each option there are sub-ratings.

The five ratings

Rating	What it means
A1	The walls are unlikely to support combustion, and there are no attachments (such as balconies) whose construction includes significant quantities of combustible material.
A2	The walls are unlikely to support combustion. Attachments include combustible material, but an appropriate risk assessment confirms no remedial works are needed.
A3	The walls are unlikely to support combustion, but neither A1 nor A2 applies, so there may be costs for remedial works to attachments.
B1	Combustible materials are present in the external wall, but the signatory has concluded the fire risk is low enough that no remedial works are required.
B2	Combustible materials are present and an adequate standard of safety is not achieved. Remedial and interim measures are required and documented separately.

Who can sign each option

Option A can be signed by a member of a relevant professional body within the construction industry. Option B needs a member of a professional body that deals with fire safety in the built environment, reflecting the more detailed fire risk judgement involved.

What the ratings mean for lending

Each lender sets its own policy, so there is no single answer. In broad terms, A1, A2 and B1 outcomes indicate that no remedial works are needed and are usually straightforward for valuation. A3 flags possible costs for works to attachments, and B2 confirms that remediation is required, which can delay or complicate a sale or remortgage until works are funded or complete.

Leaseholders in qualifying leases may also be protected from paying for cladding remediation under the Building Safety Act 2022, and remediation may be funded through the Cladding Safety Scheme. Lenders increasingly look at this evidence alongside, or instead of, an EWS1.

Getting to a reliable rating

A rating is only as good as the evidence behind it. A desk-based review may be enough for some buildings, but where records are incomplete, targeted opening-up of the wall gives a definitive answer. Our Loft Lines case study shows how construction records and opening-up were combined to reach an A1 outcome.

Frequently asked questions

What is the best EWS1 rating?

A1 is the most straightforward outcome: the external walls are unlikely to support combustion and there are no attachments with significant combustible material. A2 and B1 also confirm that no remedial works are needed.

Is a B1 rating bad?

No. B1 means combustible materials are present, but a fire safety professional has concluded the risk is low enough that no remedial works are required.

What does a B2 rating mean for leaseholders?

B2 means remedial and interim measures are needed. Leaseholders in qualifying leases may be protected from cladding remediation costs under the Building Safety Act 2022, and works may be funded through the Cladding Safety Scheme.

Can an EWS1 rating change?

Yes. A new assessment can be carried out after remedial works, or sooner if new information comes to light. Each EWS1 is valid for up to five years.

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