Flat Conversions New Cross

Flat conversions in New Cross start from the houses that are still whole: terraced houses make up 25% of homes in the VOA count for New Cross Gate, New Cross South and Telegraph Hill, against 72% flats. Splitting a house into self-contained flats needs planning permission, and Lewisham's Policy HO2 expects a family sized home to be re-provided unless the property is unsuitable for families. We build the approved scheme, with fire separation, sound insulation, separate services and room sizes worked out before the first stud wall goes up.

In New Cross, 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 New Cross: 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.

Lewisham's family housing test for a New Cross conversion

A house to flats conversion in New Cross normally has to keep a family home in the mix. Lewisham Local Plan Policy HO2 supports turning a single family dwelling or a 3+ bedroom unit into smaller self-contained flats only where set criteria are met. One of those is that the scheme re-provides a family sized unit of 3 or more bedrooms, unless the house is shown to be unsuitable for family accommodation. A terrace split into studios alone does not normally fit that policy.

In practice this sets the layout of a New Cross conversion. The larger unit can take the ground floor and garden, with a smaller flat above, and the stair is arranged so each unit has its own front door off a protected hall. The London Plan small sites text lists residential conversions that add homes among the forms of incremental intensification, which is the wider backdrop to HO2. Your designer or planning agent makes the application, and we price the build from the drawings.

Housing in New Cross

For New Cross the Council Tax list gives about 12,080 homes; by type 72% flats and 28% houses, by age 49% post-war, 2% interwar and 43% older than 1919. Since most homes here are flats, a flat in New Cross can be split or combined only with the freeholder's consent, and changing the number of homes usually needs planning permission as well.

Room sizes and ceiling heights in a converted New Cross house

The London Plan space standards apply to conversions as well as new build, since its table treats a new dwelling as including conversions and change of use. Under Policy D6 a one-bedspace single bedroom must be at least 7.5 square metres and at least 2.15m wide, and a two-bedspace double or twin bedroom needs at least 11.5 square metres. Lewisham Policy QD8 asks housing proposals to meet and where possible exceed these standards. In a narrow New Cross terrace, the back bedroom on each floor is where the figures bite.

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. Victorian upper floors can fall short once new floors are built up for sound insulation, so we measure existing heights at survey and tell your designer what the build-up leaves. GOV.UK notes that the Nationally Described Space Standard sits in the planning system, not the building regulations, so in New Cross these sizes are settled at planning stage.

Fire separation and sound testing between New Cross flats

Splitting a house is a material change of use, so the building regulations apply to the whole result, not just the new walls. Part B asks for fire separation between the flats and a protected escape route: fire resisting floors between units, fire doors onto the common stair, detection linked as the fire strategy requires, and fire-stopping wherever pipes and cables cross. The strategy comes from your designer and building control, and in a New Cross terrace we open the old floors and build it in before anything is boarded.

Part E sets the sound standard. Approved Document E sets at least 43 dB airborne for walls and floors in flats formed by a change of use, and 64 dB maximum impact for floors and stairs. A bare Victorian timber floor is not built to that standard, so we add resilient bars, insulation and heavier boards to the ceilings below and a floating layer above. Pre-completion sound testing follows, and we leave time in the New Cross programme for it before decoration.

Separate services, addresses and neighbours in a New Cross conversion

Each new flat in a New Cross conversion needs to stand on its own. That means a separate electricity supply and meter, a separate gas supply or electric heating, its own water supply where the water company requires it, and drainage that does not run through another flat without access. Lewisham uses a full plans application for any new proposal to build above or within 3 metres of a drain or sewer, so the drain runs are traced before the building control route is chosen. New flats also need addresses through the council's street naming and numbering service.

Party walls come into it when the work cuts into a wall shared with the house next door, such as new steel bearings or a chase for a stack. Lewisham Building Control says the Party Wall Act is a civil matter it does not administer, so the building owner serves any notices, and the work proceeds on written consent or an agreed award. New dwellings can also fall under Lewisham's CIL, levied since 1 April 2015, and your designer checks liability before work starts.

• Heating and hot water for each flat, gas by a Gas Safe registered engineer
• New soil stacks, wastes and bathrooms stacked floor over floor
• Decoration, flooring and making good throughout, ready to let or sell

VOA Council Tax stock of properties, March 2025, for New Cross Gate, New Cross South and Telegraph Hill. Counts rounded by the VOA.

For the wider picture around flat conversions in New Cross, see structural alterations in New Cross, flat conversions across Lewisham, building control sign-off for a conversion, refurbishing a flat that has already been converted, how we handle flat conversions across London and Structural Engineer Report Cost.

Why New Cross Homeowners Choose GS Renovation

You get one team for the structural, fire and acoustic work a conversion depends on. We build to the approved drawings, follow your structural engineer's details for any new openings, and give you a written programme with the building control stages and the sound test marked. Our founder has more than thirty years of hands-on experience. A registered electrician certifies the wiring and alarms in each flat, and a registered gas engineer handles any boilers, so each unit is handed over with its own paperwork.

• Full plans application to building control, never a building notice
• Registered in England, Companies House no. 14611254
• Every flat checked against the space standard before the layout is priced

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.