Section 257 HMO London — Converted Block Compliance

A Section 257 HMO is a building converted entirely into self-contained flats where the conversion does not meet 1991 Building Regulations standards and where less than two-thirds of the flats are owner-occupied. The definition sits at Section 257 of the Housing Act 2004. A typical example is a Victorian terrace split into three or four flats in the 1970s, sold on long leases, where one or more flats has reverted to letting.

The Section 257(1) test requires the building to be entirely converted into self-contained flats, and the conversion not to meet the standards specified in the 1991 Building Regulations. A building is excluded from Section 257 where two-thirds or more of the flats are owner-occupied — the threshold for council intervention is set at where letting dominates over owner-occupation in the building.

The 1991 Building Regulations introduced modern fire-stopping, compartmentation and means-of-escape standards for converted dwellings. Conversions before 1991 typically do not meet those standards — old plasterboard partitions, no fire-rated doors between flats, no emergency lighting in communal stairs. Section 257 captures buildings where the historic conversion creates a fire-safety risk that contemporary regulations would not allow.

Schedule 14 of the Housing Act 2004 applies to every Section 257 HMO regardless of licensing status. The manager (the freeholder or appointed managing agent) has named duties on fire safety, electrical safety, gas safety, water supply, drainage, waste storage and communal-parts repair. The duties apply continuously — failure to comply is a criminal offence with civil penalty alternative.

The Regulatory Reform (Fire Safety) Order 2005 requires a written Fire Risk Assessment for the communal parts of every HMO, including Section 257 buildings. The current methodology is PAS 79-2:2020 for housing FRAs. The Building Safety Act 2022 adds additional requirements where the building is above 18m or 7 storeys (Higher-Risk Buildings under the BSA gateway regime).

Only where the local council has declared an additional licensing scheme covering Section 257 conversions. Brent, Newham, Tower Hamlets, Hackney and several other London boroughs include Section 257 buildings in their additional schemes. Always confirm against the council's current designation. Where the scheme applies, operating unlicensed exposes you to a £30,000 civil penalty per breach.

Yes. The £30,000 civil penalty applies to the current manager regardless of when the conversion happened. Many Victorian and Edwardian London terraces were converted in the 1970s and 1980s without modern fire-stopping; the freeholder today inherits the management duty under Schedule 14. A Section 257 status assessment costs £195 and tells you exactly where you stand.

A Section 257 HMO requires fewer than two-thirds of the flats to be owner-occupied. A 4-flat building with 3 owner-occupiers and 1 let flat is not a Section 257 HMO (75% owner-occupation). A 4-flat building with 2 owner-occupiers and 2 let flats is a Section 257 HMO (50% owner-occupation). The ratio is assessed at the date of any enforcement or licensing decision.

A Section 257 building is not captured by mandatory licensing because each flat is self-contained. Mandatory licensing under Section 254 requires shared facilities (kitchen, bathroom, WC). The licensing route for Section 257 is additional licensing where the council has declared a scheme. The fire-safety and management duties under Schedule 14 and the RRO 2005 apply regardless of licensing.

Section 257 work covers a building, not a single dwelling. The assessment includes the two-thirds test, the pre-1991 conversion confirmation, the Schedule 14 audit across multiple flats and the communal-parts FRA. The evidence schedule a council expects is materially larger than a single-flat HMO application. The £500 covers the lot in one engagement.