HMO Conversions Merton

HMO conversion in Merton always starts with planning. The council has removed permitted development rights across the whole borough for turning a family house into a small HMO, so even a shared house for three tenants needs permission first. Licensing then sets the standard the building must reach: room sizes, kitchens, bathrooms and fire safety. With 58% of Merton homes being houses, the typical project is a terrace or semi turned into a shared house, or an existing HMO upgraded so its licence can be granted or renewed.

In Merton, a light HMO conversion for four to six tenants typically costs £40,000 to £75,000 in construction, or £90,000 to £150,000 with an en-suite to every bedroom (indicative London ranges, Mayfair Studio and LetCompliance, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Merton: we build the fire doors, detection, bathrooms and kitchens to the council's HMO standards, the landlord applies for the licence, and a registered electrician certifies the electrics.

Merton's HMO Article 4 covers the whole borough

In Merton a change from a family house to a small HMO needs planning permission everywhere in the borough. Nationally, Class L of the General Permitted Development Order 2015 lets a Class C3 house become a Class C4 HMO without an application, but Merton has removed that right borough-wide. An immediate Article 4 Direction covered seven wards from 17 November 2022, and another covered 13 wards, including Lower Morden, Wimbledon Park and Wimbledon Town, from 24 March 2026.

Larger HMOs were never permitted development. The London Plan glossary defines HMOs for three to six people as Use Class C4 and those for more than six people as sui generis. A shared house for seven or more people in Merton therefore needs a full planning application in any case. Class L also does not allow one former house to become two or more separate C4 HMOs. The owner or their agent applies, and our programme starts once the decision and its conditions are known.

Housing in Merton

Count the homes in Merton and you get about 87,830: 36% built since 1945, 37% between the wars and 26% before 1919, with flats at 42% and houses at 58%.

Which HMO licence a Merton shared house needs

A Merton HMO needs a mandatory licence where 5 or more people forming more than one household live in it and it is not a purpose-built flat in a block of 3 or more flats. GOV.UK defines an HMO as a property rented out by at least 3 people who are not from 1 household but share facilities like the bathroom and kitchen, and it says renting out an unlicensed HMO can lead to an unlimited fine.

Smaller HMOs can be caught too. Merton's Cabinet agreed that selective and additional landlord licensing in Merton would come into effect in September 2023, so a shared house below the mandatory threshold may still need a licence if the additional scheme covers it. The landlord applies for the licence and pays the fee; we build to the standards the licence will be tested against, so the inspection finds the rooms, kitchens and fire precautions already in place.

Room sizes and amenity standards for a Merton HMO

Merton's HMO room size standards are 6.51 square metres for one person over 10, 10.22 square metres for two people over 10 and 4.64 square metres for a child under 10. A room smaller than 4.64 square metres cannot be a bedroom, and only floor space with a ceiling higher than 1.5 metres counts. In a Merton terrace that rules out many box rooms and low attic spaces as lettable bedrooms, so the room count is fixed on the survey drawings.

Kitchens and bathrooms follow the head count. Each shared kitchen in a Merton HMO can serve no more than 5 persons, with a minimum of 2m2 of kitchen per person and worktops in a ratio of one to every three persons sharing. For 6 to 10 occupants you need at least 2 bathrooms and 2 toilets, one toilet separate with a wash hand basin. A letting with its own cooking and washing facilities must be 13m2 or more for one person and 20.5m2 for two.

Fire safety, sound and energy in a Merton shared house

Fire safety is the biggest building item in a Merton HMO conversion. Bedroom doors onto the escape route become fire doors with self-closers, the stair and hall become a protected route to the front door, and a linked detection and alarm system covers the house. LACORS housing fire safety guidance is the recognised guide to the level each house needs, and building control checks the Part B work where the conversion is building work.

Sound and energy matter to tenants and to the licence. We add insulation and resilient ceilings between bedrooms where the floor is timber, because shared houses have more people on different hours. MEES applies to HMOs as to any let: since 1 April 2020 a property covered by the regulations cannot be let with an EPC rating below E without a valid exemption. Merton Policy H11.5 also resists the net loss of HMOs, so a licensed HMO is hard to take back to a house.

• Separate WCs and wash basins to the amenity standard
• Shared kitchens enlarged or added for the number of occupants
• Small HMO conversions for three to six sharers

VOA Council Tax stock of properties, March 2025, for all 25 statistical areas in Merton. Counts rounded by the VOA.

For the wider picture around hmo conversions in Merton, see bathroom renovation in Merton, our Merton area guide, bathroom fitting in London, how snagging works at handover, how we handle hmo conversions across London and Central Heating Installation Cost.

Why Choose GS Renovation in Merton

An HMO conversion is judged twice, once by planning and once by the licence inspection, and the building has to satisfy both. We price from the approved drawings, check every bedroom against the Merton room sizes and every kitchen against the head count, and build the fire precautions to the standard the licence expects. One team handles the strip out, the partitions, the kitchens and bathrooms, the fire doors and the alarm installation with the electrician, and hands over a house ready for the licence visit.

• Registered in England, Companies House no. 14611254
• Kitchens and bathrooms counted against the council's amenity standard
• Fire doors, closers and seals fitted to every door on the escape route

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254).