Section 257 HMOs in Harrow: Licensing Rules for Converted Flats

Section 257 of the Housing Act 2004 catches a category of property that many landlords and leaseholders don't expect: converted buildings with self-contained flats. If the conversion didn't meet the Building Regulations in force at the time (typically the 1991 regulations) and less than two-thirds of the flats are owner-occupied, the building as a whole can be classified as an HMO — even though each flat is self-contained.

In Harrow, Section 257 buildings are included in the Part 2 licensing framework.

When Section 257 Applies

Three conditions must be met:

1. The building has been converted into self-contained flats. It started as a single dwelling (or commercial unit) and was divided.
2. The conversion didn't comply with the Building Regulations 1991 (or whatever regulations were in force at the time of conversion). Older Victorian and Edwardian conversions should be checked against the standards applicable to the conversion work.
3. Less than two-thirds of the flats are owner-occupied. If most flats are rented out on short tenancies, the threshold is met.

When all three conditions are satisfied and more than one-third of the flats are let on short tenancies, the building is treated as an HMO for licensing purposes.

Who Holds the Licence

This is where it gets complicated. For a standard HMO, the licence is held by the person in control — usually the landlord letting individual rooms. There is not a one-size-fits-all answer for who should hold a Section 257 building licence; leaseholders should check with Harrow's Private Sector Housing team which person or entity it expects to apply for the building.

Leaseholders in a converted block who rent their flat out should check whether the building has the necessary licence and clarify the application and responsibility position with the council.

How Fees Differ

Section 257 buildings have specific fee scales in Harrow. The HMO fee schedule lists a £100 inspection fee for a self-contained unit and £500 for a standard HMO; check with the council which category applies to a Section 257 building. The overall licence fee can be substantial for a building with many flats.

Common Confusion

Leaseholders often don't realise their building falls under Section 257. They think of their flat as a standard buy-to-let, not an HMO. The trigger isn't how the individual flat is occupied — it's the building's conversion history and the overall occupancy profile.

Another common mistake is confusing Section 257 obligations with the selective licensing wards. A Section 257 building sitting in a non-designated ward still needs an HMO licence under Part 2 if it meets the criteria. The HMO licence requirement is borough-wide.

If you own or manage a property in a converted block in Harrow, the first step is establishing the building's conversion date and Building Regulations compliance. That determines whether Section 257 applies. Our Harrow landlord licensing guide covers the full classification hierarchy including Section 257 and how it fits with the other licensing regimes.

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