EWS1 Forms Explained What They Are and When You Need One

In June 2017, seventy-two people died in the Grenfell Tower fire in west London. The investigation that followed exposed something deeply uncomfortable: thousands of residential buildings across the UK had external wall systems that hadn't been properly assessed for fire safety. Cladding, insulation, balconies, timber framing, all of it had been signed off under rules that, it turned out, weren't fit for purpose.

The mortgage market froze almost overnight. Lenders had no way of knowing whether a flat they were lending against was safe, and they weren't willing to find out the hard way. The EWS1 form, which stands for External Wall System one, was introduced in December 2019 by UK Finance and the Building Societies Association as a way to give lenders a consistent, standardised assessment they could actually rely on.

It isn't a government document, and it isn't a legal requirement. But in practice, if your lender asks for one and you can't produce it, you're not getting a mortgage. That makes it feel very much like a legal requirement to most buyers.

An EWS1 is completed by a qualified professional, usually a fire engineer or a chartered surveyor with the right qualifications, who physically inspects the external wall construction of a building. They're looking at what the walls are made of, whether there's combustible insulation, what the cladding panels are, and whether any of it poses an unacceptable fire risk.

The form has two possible outcomes. An A rating means the external wall materials are unlikely to support the spread of fire. A B rating means they might. Within each of those there are numbered sub-categories that get more specific. An A1 or A2 result is generally good news and most lenders will be happy. A B1 result means remediation is needed but the risk is considered acceptable. A B2 result is the one that causes real problems because it means the assessor has concluded the building isn't safe in its current state.

If the building gets a B2, lenders won't lend against flats in it. Full stop. The building needs to be fixed before that changes.

This is where it gets a bit more nuanced, and where a lot of buyers get confused. Not every flat in the country needs an EWS1 form. The guidance has shifted a few times since 2019, and the current position from the Royal Institution of Chartered Surveyors, updated in 2021, is more targeted than the original blanket approach.

Generally speaking, buildings of eleven metres or above in height, which is roughly four storeys, are in scope. Below that height, an EWS1 is less commonly required, though individual lenders can still ask for one if they have concerns. Buildings over eighteen metres, roughly six storeys, face the most scrutiny because that's where the government's remediation funding programmes are primarily focused.

Beyond height, the key trigger is whether the building has cladding or other potentially combustible materials on its external walls. A brick-clad low-rise block with no additional insulation system is in a very different position to a high-rise with aluminium composite panels or expanded polystyrene insulation. Your solicitor and surveyor should be able to give you a steer early in the process, but the honest answer is that if the building is over four storeys and has anything other than brick or stone on the outside, you should expect the question to come up.

This is the practical bit that catches buyers off guard. You find a flat you love, you make an offer, and then your mortgage surveyor flags that the building needs an EWS1 and one doesn't exist. What now?

First, don't panic, but do be realistic. Getting an EWS1 assessment commissioned is the responsibility of the building owner or the freeholder, not you as a buyer. You can't just pay for one yourself and hand it over. The freeholder has to arrange it, and qualified assessors are still in short supply in many parts of the country. Waiting times can run to many months.

If the building is covered by one of the government's remediation schemes, particularly if it's over eleven metres and the developer is still trading, there may be a Developer Remediation Contract in place. That's worth checking through your solicitor because it can affect both the timeline and who's paying for the work. The Building Safety Act 2022 created legal routes to make developers and building owners pay for historic cladding defects, which is genuinely good news, but it doesn't make the process fast.

Some lenders are more flexible than others. A handful will lend on buildings without an EWS1 if the surveyor is satisfied there's no cladding risk. It's worth asking your mortgage broker specifically about this rather than assuming all doors are closed.

A missing or poor EWS1 result doesn't just affect whether you can get a mortgage. It affects what the flat is worth, what you can sell it for in the future, and what your service charge looks like while you own it.

If remediation work is needed and the freeholder or developer isn't paying, leaseholders can face enormous bills. The Building Safety Act 2022 introduced protections that limit what qualifying leaseholders can be charged, and in many cases the costs should fall on the building owner or developer entirely. But the protections depend on your specific situation, when the lease was granted, what the building height is, and other factors. You need a solicitor who understands building safety law, not just conveyancing, before you exchange.

On the mortgage side, some lenders have pulled out of the affected market altogether. Others will lend but only at lower loan-to-value ratios, meaning you'd need a bigger deposit. Your broker needs to know the building's situation before they recommend a product, because placing you with the wrong lender wastes everyone's time.

Service charges in affected buildings can also be significantly higher while remediation is ongoing, covering things like waking watch fire patrols if the building's fire alarm system doesn't meet current standards. These costs can run to thousands of pounds a year per flat. Ask the seller's solicitor for the last three years of service charge accounts before you commit to anything.

The single most useful thing you can do before making an offer on a flat is ask the estate agent directly whether an EWS1 exists and what the result was. They should know. If they don't, that tells you something.

Once you're in the conveyancing process, your solicitor should raise building safety enquiries as standard. If they don't mention it, ask. You want to know whether there's an EWS1, what the rating is, whether any remediation work is planned or underway, who's funding it, and whether there are any interim fire safety measures in place that are costing leaseholders money.

Get a full buildings survey, not just a mortgage valuation. A good surveyor will look at the external walls and flag anything that looks like it could cause problems. It costs more upfront but it's far cheaper than buying a flat and then discovering you can't sell it.

Finally, talk to your mortgage broker before you fall in love with a property. Give them the address, the building height, and any information you have about the external walls. A good broker will tell you honestly which lenders are likely to play ball and which aren't, saving you a lot of heartache down the line.

The EWS1 system was always meant to be a temporary fix while the building safety crisis was resolved. The honest truth is that resolution is taking much longer than anyone hoped. Thousands of buildings are still waiting for assessments or remediation, and the qualified workforce to do that work is still being built up.

The government has made commitments and passed legislation, and the Building Safety Act 2022 is genuinely significant. But legislation and reality don't always move at the same speed. If you're buying a flat in a building that's affected, you need to go in with your eyes open about the timeline, the costs, and the uncertainty.

That said, the market hasn't collapsed. Flats with clean EWS1 results are trading normally. Buildings where remediation is funded and underway are becoming mortgageable again as the work completes. The situation is improving, just not as fast as anyone would like.

If you're a first time buyer and you're worried about all of this, the simplest advice is to focus on buildings that already have a positive EWS1 result. It narrows your options, but it removes a huge amount of risk and uncertainty from what is already one of the biggest financial decisions of your life.