If you rent to three or more people from different households who share a kitchen, bathroom or toilet, you may have an HMO — and significant legal obligations come with it. This guide explains exactly what an HMO is, when you need a licence, and crucially, what your fire door obligations are.
The Legal Definition of an HMO
Under the Housing Act 2004, a property is an HMO if it is occupied by three or more people forming two or more households, and at least one of the following applies:
- They share toilet, bathroom or kitchen facilities, or
- It is a converted building that does not consist entirely of self-contained flats
Key Definition: "Household"
A household is a single person, or a group of people related by blood, marriage, civil partnership or are in a romantic relationship. Three friends sharing a house = 3 separate households = HMO.
Types of HMO in London
HMOs come in many forms across London:
- Shared houses: 3–5 friends renting a terraced house together
- Bedsits: Individual rooms with shared facilities
- Student houses: Multiple students from different families
- Supported accommodation: Hostels, refuges, supported living
- Converted flats: Some buildings converted before 1991 building regulations
Fire Door Requirements for London HMOs
This is where many landlords fall short. HMO fire door requirements are not optional — they are a condition of your HMO licence and a legal obligation under the Regulatory Reform (Fire Safety) Order 2005.
- All habitable rooms opening onto escape routes need FD30S doors
- The kitchen door needs an FD30S door
- All fire doors need intumescent strips AND smoke seals
- Minimum 3 fire-rated hinges per door
- A self-closing device on every fire door
- Maximum 3–4mm gap around the door leaf when closed
Not sure if your HMO fire doors are compliant? Doorz London carries out fire door inspections with a full written report across all London boroughs.
Book Fire Door Inspection →London Borough Licensing Schemes — 2026
Beyond mandatory licensing, many London boroughs run additional licensing schemes. Key boroughs as of 2026:
- Newham: Selective licensing across much of the borough
- Brent: Additional HMO licensing borough-wide
- Hackney: Additional licensing across most of the borough
- Southwark: Selective licensing in several wards
- Haringey: Additional licensing scheme in operation
- Lambeth: Selective licensing in multiple areas
Always check your specific borough's licensing portal before letting any property. Unlicensed HMOs face fines of up to £9,000 and a Rent Repayment Order from tenants.
Read our full guide to the 2025-26 HMO and tenant law changes including the Renters Rights Act.
Read Full Law Guide →