What is a S257 HMO?

 

Section 257 HMOs (after s257 of the Housing Act 2004) are buildings which has been converted, or part converted, into self-contained flats that did not comply with the appropriate building standards and still do not comply with those standards, and less than two-thirds of the self-contained flats are owner occupied.

Buildings converted into self-contained flats will generally not be S257 HMOs, provided that they were converted in accordance, or now comply, with the appropriate building standards required at the time of the conversion.

A building is an HMO under s257 if all three of these apply:

  • The building has been converted into self-contained flats

  • The conversion does not meet the appropriate Building Regulations (i.e. not in accordance with 1991 standards or later)

  • Less than two-thirds of the flats are owner-occupied (the rest are rented out)

 

The appropriate building standards, as a minimum, will be the 1991 Building Regulations. If you don’t have a building certificate for the conversion, it’s very likely your building is a s257 HMO. Please seek advice, but don’t phone or contact the local authority to ask!

Often these blocks were converted into flats before 1st June 1992 and did not comply at that time with the Building Regulations 1991.

The Section 257 HMOs, are not C4 dwellings, but are subject to licensing where additional or selective licensing is in place. 

What this means in practice

  • Even though each flat may be self-contained, the building as a whole is classed as an HMO

  • The landlord or freeholder (or managing agent) may have HMO-related responsibilities for the entire building, especially around fire safety, common areas, and maintenance

  • Some councils require HMO licensing for s257 buildings if they meet their local scheme criteria (especially additional licensing schemes)

 

S257 HMO

 

S257 licensing

 

Unlike most other HMOs, Section 257 HMOs are not automatically subject to mandatory licensing. S257 HMOs are subject to licensing where additional or selective licensing is in place. This will vary depending upon the local authority. So please check locally.

Additional Licensing – Additional Licensing requires houses in multiple occupation shared by 3 or 4 unrelated people who are forming 2 or more households and who share facilities such as kitchens and bathrooms, to have a licence. Although the legislation refers to ‘houses’ this does cover a variety of housing types including flats. The scheme must include S257 HMOs. Not all do within their additional licensing framework.

Selective Licensing – Selective Licensing requires most private rented properties within a designated area to be licensed. It means that houses need to be licensed where they have a family or one or two tenants living there. Like Additional Licensing, although the legislation refers to ‘houses’ this does cover a variety of housing types including flats.

Typical conditions of a licence (if required)

  • Fire-safety upgrades (FD30S doors, interlinked alarms, emergency lighting)

  • Management of common parts (lighting, refuse, structural maintenance)

  • Periodic inspection records and gas/electrical safety certificates

  • Apply through the council’s portal (typically Part 2 HMO licence form)

  • Provide layout plans, fire-risk assessment, and safety certificates

If licence not required

  • Still ensure compliance with HMO Management Regulations 2006 (especially for fire safety and maintenance)

  • Fire Safety Order 2005 for communal areas

  • Keep a written fire-risk assessment and record of safety checks

 

S257 HMO Action Plan

 

If you own or manage a converted building:

  • Check whether the conversion met 1991 Building Regs standards

  • Confirm how many flats are owner-occupied

  • If less than two-thirds and not compliant, it’s a s257 HMO

 

If so:

  • Review your council’s HMO licensing policy — you may need to apply for a licence

  • Ensure fire precautions, common-area maintenance, and management standards comply with The Management of HMOs (England) Regulations 2006

  • Keep proper records for safety inspections and repairs

 

Section 254 HMO

 

Section 254 HMOs (after the section in the Housing Act 2004 that describes them) are buildings where there are the sharing of some basic amenities. These are the types of properties that people most associate with HMOs, such as shared student houses or bedsit accommodation, where the bedsits share kitchens and / or bathrooms, etc. These are generally C4 or Sui Generis HMOs.

 

 

Page updated: 29th October 2025

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