The Building Safety Act Explained: What Flat Buyers Need to Know

The Grenfell Context

The Grenfell Tower fire in June 2017 killed 72 people and exposed systemic failures in building safety regulation. Investigations revealed that combustible cladding — aluminium composite material (ACM) with a polyethylene core — had been installed on the tower despite being known to be a fire risk. The subsequent inquiry found failures at every level: manufacturers, architects, contractors, building control, and government.

In the aftermath, the government identified over 12,000 residential buildings in England with potentially unsafe cladding. Hundreds of thousands of leaseholders found themselves trapped in unsellable, unmortgageable homes, facing bills of £40,000–£100,000 or more for remediation work they had no part in causing. The Building Safety Act was designed to fix the regulatory failures and protect leaseholders from these costs.

The Act received Royal Assent in April 2022 and its provisions have been rolling out in phases since then. It represents the most significant change to building safety law in a generation, creating new regulatory bodies, new duties for building owners, and new protections for residents.

Leaseholder Protections

The Building Safety Act's most impactful provisions protect qualifying leaseholders from the cost of historical building safety defects. If your building was constructed or refurbished before 28 June 2022 and has safety defects (including but not limited to cladding), the Act restricts who can be required to pay for remediation.

Qualifying leaseholders — broadly, those who owned their flat on 14 February 2022 (or purchased from someone who did) and who don't own more than two properties in the UK — are protected from remediation costs in most circumstances. For buildings over 11 metres, the developer, building owner, or other responsible parties must pay. For buildings 11–18 metres, leaseholders are protected by a cap of £10,000 (£15,000 in London) on non-cladding defect costs, though cladding remediation costs cannot be passed on at all.

These protections are powerful but not universal. If you bought your flat after 14 February 2022 from someone who was not a qualifying leaseholder, you may not inherit the protections. Buy-to-let investors with large portfolios may not qualify. Your solicitor should verify your qualifying status as part of the conveyancing process.

EWS1 Forms and Building Safety Certificates

The External Wall System (EWS1) form was introduced by RICS, UK Finance, and the Building Societies Association as a way for mortgage lenders to assess fire risk in buildings with external wall systems. A qualified fire engineer inspects the building's external walls and rates them from A1 (no combustible materials, no remediation needed) to B2 (combustible materials present, remediation needed).

A B2 rating effectively made properties unmortgageable when EWS1 was first introduced, as most lenders would not lend on a flat in a building requiring remediation. The situation has improved — many lenders now take a more nuanced view, particularly if a remediation plan is in place — but EWS1 remains a significant factor in flat purchases.

The Building Safety Act introduced Building Assessment Certificates for higher-risk buildings (those over 18 metres or with at least 7 storeys). The new Building Safety Regulator (part of the HSE) oversees these buildings and requires Principal Accountable Persons to register their buildings and demonstrate compliance with safety requirements. This is an ongoing regulatory requirement, not a one-off check.

The Building Safety Fund and Remediation Programmes

The government established several funding programmes to pay for remediation of unsafe buildings. The Building Safety Fund (now the Cladding Safety Scheme) provides funding for buildings over 11 metres with unsafe cladding. The Social Housing Decarbonisation Fund and various developer pledges also contribute to remediation costs.

Over 50 major developers signed the government's Developer Remediation Contract, committing to fix life-critical fire safety defects in buildings they developed over 11 metres tall. This covers cladding and other external wall defects. Developers who refused to sign face restrictions on building control approval for new projects.

The reality on the ground is that remediation is happening, but slowly. As of 2026, thousands of buildings are still awaiting assessment, funding approval, or the start of physical works. Leaseholders in affected buildings may face years of uncertainty, interim fire safety measures (such as waking watches costing thousands per month), and restrictions on selling.

What to Check When Buying a Flat

Before buying any flat, and especially one in a building over 11 metres, you need to investigate fire safety thoroughly. Start by asking for the EWS1 form — if one has been done, the rating tells you the current assessment of the external wall system. If no EWS1 has been done, that itself is information — it may mean the building hasn't been assessed yet.

Request the building's fire risk assessment (FRA), which is a legal requirement for all buildings with common areas. The FRA should be recent (within the last 1–2 years) and should identify any 'actions required'. Ask whether those actions have been completed. Also check whether the building has a Building Safety Case (required for higher-risk buildings under the Act).

Check your mortgage lender's position before making an offer. Some lenders will not lend on buildings with outstanding EWS1 B2 ratings, buildings in the process of remediation, or buildings that haven't yet been assessed. Others will lend with conditions. Your mortgage broker should confirm the lender's stance on the specific building before you commit.

• ▸EWS1 form: Request the current rating — A1 is ideal, B1 may need monitoring, B2 means remediation needed
• ▸Fire risk assessment: Must exist for all buildings with common areas — check it's recent and actions are completed
• ▸Remediation status: Ask if works are planned, in progress, or completed — and who is paying
• ▸Building Safety Regulator: For buildings over 18m, check the building is registered and has a Principal Accountable Person
• ▸Service charge impact: Ask how fire safety costs are reflected in current and projected service charges

Higher-Risk Buildings: 18 Metres and Above

Buildings over 18 metres (approximately 7 storeys) are classified as 'higher-risk buildings' under the Building Safety Act and are subject to the most stringent requirements. They must be registered with the Building Safety Regulator, have a named Principal Accountable Person responsible for building safety, and maintain a 'golden thread' of building information — a comprehensive, up-to-date record of the building's design, construction, and safety systems.

Residents in higher-risk buildings have enhanced rights under the Act, including the right to request information about the building's safety and the right to make complaints to the Building Safety Regulator. The Regulator has powers to issue compliance notices, impose penalties, and — in extreme cases — take over the management of a building.

For buyers, higher-risk buildings require extra due diligence but are not automatically a bad investment. A building that has completed remediation, has a clean EWS1 rating, and is properly registered with the Regulator may actually be a safer purchase than one that hasn't been assessed at all. The key is to verify the current status and understand any ongoing obligations or costs.

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