Flat Conversions Greenwich

A flat conversion in Greenwich turns one house into two or more self-contained flats, or occasionally puts flats back together as a house. Royal Greenwich's Urban Design Guide says house-to-flat conversions need planning permission, and the new flats must meet the same minimum internal space standards as new dwellings. The raw material is the borough's houses: terraced houses are 31% of homes and 22% of homes predate 1919, and only the larger ones have the floor area for two flats. We build to the approved drawings: separating floors, protected stairs, new kitchens and bathrooms, and separate services.

In Greenwich, 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 Greenwich: 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 a house into flats conversion in Greenwich

Planning permission comes first, and there is no permitted development route for splitting a Greenwich house into flats. Royal Greenwich's Urban Design Guide says any extension added as part of the scheme should meet the same minimum space standards as new homes, so a rear addition that makes a layout work has to pass the same tests. The London Plan counts residential conversions among the forms of small-site intensification where they result in net additional housing.

Two local checks can change the scope. Where the house is in Flood Zone 2 or 3, Royal Greenwich requires a Flood Risk Assessment for all developments there, including domestic extensions, so the ground floor flat may need raised levels or flood-resilient finishes. Royal Greenwich's CIL charging schedule, adopted on 24 July 2024, sets a rate for residential development of less than 10 units, so your agent confirms whether the new floorspace is liable before the programme is fixed.

Housing in Greenwich

By the valuation list's count, Greenwich holds about 125,080 homes, 45% houses and 55% flats; by age, 22% were built before 1919, 17% between the wars and 60% since 1945. Since most homes here are flats, changing the number of flats in Greenwich needs the freeholder and usually planning.

Space standards for self-contained flats in Greenwich

The London Plan space standards table states that a new dwelling includes conversions and change of use, so a converted Greenwich flat is measured like a new build. Under Policy D6, a one-bedspace single bedroom must be at least 7.5 square metres and 2.15m wide. A two-bedspace double or twin bedroom needs at least 11.5 square metres. Where borough plans set no higher standard, Policy D6 also asks for at least 5 square metres of private outdoor space for 1 to 2 person dwellings, plus 1 square metre for each additional occupant.

Policy D6 also sets a minimum floor to ceiling height of 2.5m for at least 75 per cent of each dwelling's Gross Internal Area. Terraced houses are 31% of the borough's homes, and in a terrace the low rear addition is where that height test tends to bite. The same policy asks for dual aspect dwellings and normally avoids single aspect ones, which favours splitting a terrace floor by floor. The designer tests the layout early and we build to it.

Sound and fire separation between Greenwich flats

Policy H(b) Conversions requires sound insulation between the new units and between them and neighbouring dwellings. Approved Document E sets the performance for flats formed by material change of use at 43 dB airborne for walls and for floors and stairs, and 64 dB maximum impact for floors and stairs. In a Greenwich house split into flats, the old timber floor between storeys is the weak point, so it usually gets a new ceiling, insulation and a resilient layer.

Fire separation under Part B of the Building Regulations follows the same lines. Each flat needs protected walls and floors, fire doors onto a protected stair and a detection system, all shown on the building control drawings. We seal every service penetration through the separating floors and walls, and we keep the work open for inspection before the ceilings close. Sound testing under Part E is done before completion on sample walls and floors, so the detailing on site has to match the drawings throughout.

Drainage, meters and neighbours on a Greenwich conversion

Every new flat needs its own services: a separate electricity meter and consumer unit, its own heating, water and a kitchen and bathroom connected to the drains. In a Greenwich terrace the new soil stacks usually run at the back, and Royal Greenwich requires a full plans application to build over or within three metres of a public sewer, which a rear addition in a terrace can be. New flats also need addresses through the council's street naming and numbering service before the utilities will connect them.

The party wall is the other shared boundary. Cutting pockets for new steels or adding sound insulation to the party wall can fall under the Party Wall Act, and the building owner serves the notices on the neighbours. We programme that work for after the neighbours consent in writing or an award is made. Royal Greenwich's charging scheme says its building control team should be advised when a building is converted, and a building notice is meant only for simple work, so plan on a full plans application for the conversion.

• Fire stopping round every pipe and cable through a separating floor
• Separating floors with independent ceilings and acoustic insulation
• House to flat conversions into two or more self-contained units

VOA Council Tax stock of properties, March 2025, for all 35 statistical areas in Greenwich. Counts rounded by the VOA.

Once you know the scope of the flat conversions in Greenwich, it helps to read structural alterations in Greenwich, our Greenwich area guide, builders in London who take on conversions, the Party Wall Act when a conversion cuts a shared wall, our London flat conversions page and House Rewire Cost.

Trusted Flat Conversions in Greenwich

A conversion is a building control job from end to end, and the order of work decides whether it passes testing. We run the strip-out, structure, separating floors, services and finishes as one programme, working to the planning consent and drawings your designer secures. A registered electrician certifies each flat's wiring and an engineer on the Gas Safe Register commissions any gas. The separating details stay open for inspection before they are covered, and you get one site contact from strip-out to sound test.

• Fire strategy for the stair and each flat entrance settled before strip-out
• Common parts, bin stores and cycle stores finished to the planning conditions
• Itemised pricing, so you can see what every stage costs

Reviewed jobs near Greenwich

1 MyBuilder review from Woolwich, with each customer's own job title:

• Replace kitchen extractor hob, Woolwich, 27 Apr 2024 (5 out of 5)

Read all 31 on our reviews page.

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.