Flat Conversions Hendon

A flat conversion in Hendon turns a house into self-contained flats, or joins flats back into one house. Houses are 38% of Hendon homes, with 24% semi-detached or detached and 13% terraced, and the larger interwar and older houses tend to have the floor area to split. Every house-into-flats scheme needs planning permission, each new flat is measured against London Plan space standards, and building regulations treat the work as a material change of use. We build to the approved scheme.

In Hendon, converting a house into two or three flats is published at £50,000 to £120,000 including professional and council fees, and an England-wide guide puts a straightforward two-flat split at £40,000 to £80,000 in construction alone, which is the part a builder prices (indicative London ranges, Architectural Drawings and Mayfair Studio, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Hendon: we build the conversion to the approved drawings, building control inspects the fire and sound separation, and a registered electrician certifies each flat's electrics.

Planning permission and Barnet policy for converting a Hendon house

Splitting a Hendon house into flats always needs planning permission, because it creates new dwellings. The London Plan counts residential conversions among the forms of small-site intensification that add net housing, so the principle has support at London level. Barnet then applies its own Local Plan, and the national Planning Data record for that document gives a start date of 4 March 2025. Ask your designer to check what it says about conversions, the loss of family homes and any minimum original house size before you commit.

For a Hendon semi or detached house, the application has to answer practical questions. How many flats does the floor area allow, is a family-sized unit with the garden kept, where do bins and bikes go, and how is each flat reached from the street? The owner, or their designer or agent, makes the application. We price from the planning drawings and flag any buildability problem early, such as a stair that cannot give a protected route, before the scheme is fixed.

Housing in Hendon

On the valuation list Hendon counts about 16,060 homes, 62% flats and 38% houses; 20% predate 1919, 37% are interwar and 43% post-war. Changing the number of flats in Hendon needs the freeholder and usually planning, which matters here because most homes are flats.

Space standards every new Hendon flat has to meet

Each flat created in a Hendon conversion counts as a new dwelling under London Plan Policy D6, whose minimum space standards apply to all tenures and all self-contained homes. A single bedroom must be at least 7.5 square metres and 2.15m wide, and a double or twin at least 11.5 square metres. Those sizes, not the number of rooms upstairs, set how many flats a house can hold. GOV.UK notes that the national space standard sits in the planning system rather than the building regulations.

Outdoor space and aspect come next. Where borough plans set no higher standard, Policy D6 asks for at least 5 square metres of private outdoor space for a 1 to 2 person home, plus 1 square metre for each additional occupant. It also prefers dual aspect homes to single aspect ones. In a Hendon house the garden tends to go with the ground floor flat, so upper flats need a balcony, a terrace or a share of the garden, and a front-to-back layout keeps each flat dual aspect.

Fire and sound separation between flats in a Hendon conversion

A conversion is a material change of use, so the building regulations reach into the existing house as well as the new work. Part B requires each flat to be its own fire compartment, with fire-resisting floors and walls between flats, a protected stair to the front door, self-closing fire doors onto it and interlinked detection. In a Hendon house with a single timber stair, that protected route decides the layout, and the top floor flat may need a second means of escape. Part L applies to the walls, roof and windows you renew.

Sound is the other test. Approved Document E sets 43 dB airborne insulation for walls, floors and stairs in flats formed by a material change of use, and a maximum of 64 dB impact sound for floors and stairs. The timber floors of a pre-1919 or interwar Hendon house rarely reach that as found, so the upgrade is a resilient ceiling, mineral wool between the joists and a floating layer above. Pre-completion sound testing checks the result, so every junction is detailed to pass it.

Meters, addresses, party walls and de-conversion in Hendon

Each new flat needs its own supplies and its own address. That means separate electricity meters and consumer units, a separate gas meter or all-electric heating, a water supply the utility is content with, and drainage the building control body has inspected. The new flats are named and numbered through Barnet Council's street naming and numbering service, which the utilities and the Land Registry rely on. Start those applications early in a Hendon conversion, because meters are often the last item holding up completion.

Two other matters sit alongside the build. Where the work cuts into a party wall, for example for new steel bearings or fire separation, the Party Wall Act applies: the building owner serves notice on the neighbours, and that work proceeds on their written consent or a surveyor's award. Some owners look at the reverse and return a converted Hendon house to a single home. Turning flats back into one house can need planning permission because it removes homes, so check with a planning adviser before relying on that route.

• New soil stacks, wastes and bathrooms stacked floor over floor
• Separating floors with independent ceilings and acoustic insulation
• Separate gas, electricity and water supplies for each flat

VOA Council Tax stock of properties, March 2025, for Hendon Central, Hendon Park, North Hendon & Sunny Hill and West Hendon. Counts rounded by the VOA.

For the wider picture around flat conversions in Hendon, see structural alterations in Hendon, flat conversions across Barnet, a building contractor for the whole conversion, refurbishing a flat that has already been converted, our London flat conversions page and Central Heating Installation Cost.

Trusted Flat Conversions in Hendon

Converting a Hendon house needs a builder who knows where the planning drawings, fire separation and sound testing meet on site. We build from the approved scheme, sequence the structural, fire and acoustic work so nothing is covered before it is inspected, and bring in a registered electrician for each new flat's circuits. The structural engineer we appoint details any new steels. You get one programme and one contact from strip-out to completion, with the test results and certificates gathered for the sale or letting of each flat.

• Building control applications and inspections coordinated for you
• Wet rooms stacked floor over floor to keep the drainage simple
• Common parts, bin stores and cycle stores finished to the planning conditions

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.