Flat Conversions Eltham

Flat conversions in Eltham start from a stock that is 73% houses, 39% of homes being semi-detached or detached and 32% terraced. A large semi or a deep Victorian terrace can be split into self-contained flats, but in Royal Greenwich a house-to-flat conversion always needs planning permission, and each new flat is measured against the same space standards as a new build. We build conversions to the approved drawings: separating floors, protected stairs, new kitchens and bathrooms, and services split so each flat stands on its own.

In Eltham, 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 Eltham: 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.

Which Eltham houses lend themselves to conversion into flats

The Eltham houses that convert best are the larger ones. With 39% of homes semi-detached or detached, and 17% built before 1919, the candidates are a wide interwar semi with a generous first floor or a tall Victorian house with high ceilings, where two flats can each take a full floor. A small two-up two-down terrace rarely has the floor area to produce two flats that meet the standards, so the first test is always the measured survey, not the asking price.

Royal Greenwich's Urban Design Guide says house-to-flat conversions need planning permission, and that any extension should meet the same minimum internal space standards as new dwellings. The London Plan counts residential conversions among the kinds of incremental intensification that matter where they add net housing, so the principle counts in a scheme's favour. Your designer or planning agent prepares and submits the application, and we price from the drawings, often at the feasibility stage, so the build cost is known before you commit.

Housing in Eltham

By the valuation list's count, Eltham holds about 14,360 homes, 73% houses and 27% flats; by age, 17% were built before 1919, 52% between the wars and 30% since 1945. The side of a semi in Eltham is where a separate entrance for the upper flat is most often placed, and 35% of homes here are semi-detached.

Space standards that decide an Eltham conversion layout

Each flat carved from an Eltham house is treated as a new dwelling. London Plan Policy D6 applies minimum space standards to all tenures and all self-contained homes, and its standards table says a new dwelling includes conversions and change of use. So the flat on the first floor of a converted semi is measured room by room and in total floor area, exactly like a flat in a new block. A layout that falls short of the numbers is exposed to refusal.

Bedrooms and ceilings are where Eltham houses are tested. A single bedroom must be at least 7.5 square metres and 2.15m wide, a double at least 11.5 square metres, and the floor to ceiling height at least 2.5m over 75 per cent of each flat's floor area. Policy D6 also favours dual aspect homes and asks for private outdoor space. We check existing ceiling heights at the survey, because a lowered ceiling for sound insulation can push a room below the standard.

Fire separation and sound testing between Eltham flats

Turning one Eltham house into two homes is a material change of use, so the building regulations for fire and sound apply in full. Royal Greenwich's Policy H(b) Conversions requires sound insulation between the new units and between them and neighbouring dwellings, which on a semi or terrace means the party wall as well as the new floor. Approved Document E sets the target for flats formed by change of use: 43 dB airborne for walls, floors and stairs, and 64 dB impact.

A typical build-up, to the designer's specification, lifts the timber floor between the flats and fills the void with mineral wool. A resilient bar and two layers of acoustic board then go on the ceiling below, which also gives the fire resistance Part B asks for. The stair to the upper flat becomes a protected escape route with fire doors, and the flats get interlinked alarms. Pre-completion sound testing checks the separating walls and floors against Part E, so the build-up is detailed to pass before the ceilings are closed.

Services, addresses and neighbours in an Eltham conversion

Each flat in an Eltham conversion needs its own supplies. That means separate electricity and gas meters, a consumer unit and boiler per flat, and water and drainage arranged so a leak or blockage in one does not shut off the other. New soil stacks and kitchen wastes often run to the rear, and Royal Greenwich requires a full plans application to build over or within three metres of a public sewer, so the drainage survey comes before the kitchen layout is fixed.

Two practical items are easy to leave late. The new flats need addresses from the council's street naming and numbering service before the utilities will set up accounts. And where the work cuts into a party wall, for fire or sound upgrades or new steel bearings, the Party Wall Act applies: the building owner serves the notices, and we build to the agreed award. Royal Greenwich also asks to be advised when a building is converted, which your designer handles with the building control submission for the Eltham house.

• Insulation to the walls, roof and floors the conversion touches
• Pre-completion sound testing arranged before sign-off
• Decoration, flooring and making good throughout, ready to let or sell

VOA Council Tax stock of properties, March 2025, for all 5 statistical areas in Eltham. Counts rounded by the VOA.

If you are weighing up options for your Eltham property, it is worth reading structural alterations in Eltham, flat conversions across Greenwich, builders in London who take on conversions, party walls in a flat conversion, our London flat conversions page and Getting Planning Permission.

Why Eltham Homeowners Choose GS Renovation

A flat conversion joins structural work, fire separation, acoustic detailing and two or more fit-outs in one job, and it is signed off on test results. We build to the approved planning drawings and building regulations design, run the separating floors, protected stair, services and finishes in order, and arrange the pre-completion sound test. A registered electrician certifies each flat's electrics, a Gas Safe Register engineer does the gas work, and you receive the certificates for each Eltham flat's completion.

• Every flat checked against the space standard before the layout is priced
• Each flat's new electrics signed off by a registered electrician for Part P
• Registered in England, Companies House no. 14611254

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.