Flat Conversions Hackney

Flat conversion work in Hackney starts from a small pool of houses. Only 17% of homes in the borough are houses, and 16% are terraced houses, so the borough's Victorian terraces are the buildings that get split into self-contained flats or brought back to one home. Each conversion needs planning permission, London Plan room sizes, fire and sound separation between the new flats, and separate services and addresses for each one.

In Hackney, 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 Hackney: 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.

Space standards for a Hackney house conversion

A Hackney house split into flats needs planning permission, which the owner or their designer applies for. The flats also have to meet the London Plan space standards, because the minimum internal space standards table states that a new dwelling includes conversions and change of use. Under Policy D6 a one-bedspace single bedroom must be at least 7.5 square metres and 2.15m wide, and a two-bedspace double must be at least 11.5 square metres. Those room sizes are the test that decides how many flats a terrace can really hold. The London Plan counts a residential conversion as small-site intensification where it adds homes, so the planning case rests on net new flats that meet those sizes.

Policy D6 also sets a minimum floor to ceiling height of 2.5m for at least 75 per cent of the gross internal area of each dwelling. In a Victorian Hackney terrace the ground and first floors often clear that, while the rear addition and the top floor may not. The designer works the layout around the tall rooms, and we build the partitions, stairs and new floors to the dimensions on the approved plans.

Housing in Hackney

The Council Tax list puts Hackney at about 120,710 homes, 83% flats against 17% houses; 35% went up before 1919, 8% between the wars and 56% after 1945. Changing the number of flats in Hackney needs the freeholder and usually planning, which matters here because most homes are flats.

Fire and sound separation between Hackney flats

Each new flat in a Hackney conversion needs fire separation from its neighbours and a protected escape route under Part B. In practice that means fire resisting floors between flats, fire doors onto a shared stair, linked smoke detection and sealed service openings. In a pre-1919 terrace the old lath and plaster ceilings rarely give enough fire resistance on their own, so new boarded ceilings go in under the upper flats.

Sound is the other test, under Part E. Approved Document E sets lower sound insulation performance for flats formed by material change of use: 43 dB airborne for walls and for floors and stairs, and 64 dB maximum impact for floors and stairs. On a Hackney timber floor we add a resilient ceiling, mineral wool in the void and a floating floor above, then leave the building ready for the pre-completion sound test. Tested walls and floors are the evidence building control needs.

Levy, party walls and addresses for new Hackney flats

Hackney Council says development under 100 square metres is not normally liable for CIL unless it is a whole dwelling, so creating a new flat brings the scheme into the levy. The charge is worked on net new floorspace, though, and existing floorspace in lawful use is normally deducted, so a house split into flats with no extension often pays little or nothing. The Mayoral CIL and Hackney's own CIL both apply in the borough, so the owner or their designer checks liability and files the forms before work starts on site.

A conversion often cuts into party walls for new steels, stairs or fire separation. That work needs party wall notices under the Party Wall etc. Act, and Hackney Council says party wall matters, including disputes, are civil matters outside its remit, so the building owner serves the notices and we start that work once consent or an award is in place. Each new flat also needs its own address through street naming and numbering, and its own electricity supply and meter, and usually its own water supply and, where gas is used, its own gas meter. Those take time to arrange with the utilities.

Turning Hackney flats back into one house

Some Hackney terraces go the other way, from flats back to a single family house. Many are Victorian houses split decades ago that now suit one household again. Because the reversal removes homes, it generally needs planning permission in London, so the owner takes planning advice first. It also needs building control for any new structural openings, stair changes and changes to the escape route. It is worth taking that advice before the strip-out is priced.

The work is mostly removal and repair. We take out the extra kitchens and the fire lobby partitions, reinstate the hall and staircase, and bring the services onto one heating system, with the suppliers arranging to merge the meters. Where the old conversion boxed in cornices or blocked fireplaces, we open them up with care. Hackney Building Control expects a completion notice within five days of the work finishing, and we keep that date in the programme.

• Bin stores, cycle stores and external works to the planning conditions
• Splitting a large flat in two, or joining two flats into one
• Separating walls built and lined for sound between flats

VOA Council Tax stock of properties, March 2025, for all 30 statistical areas in Hackney. Counts rounded by the VOA.

Useful next reading for a flat conversions project in Hackney: structural alterations in Hackney, our Hackney area guide, a building contractor for the whole conversion, refurbishing a flat that has already been converted, flat conversions anywhere in London and House Rewire Cost.

Why Hackney Homeowners Choose GS Renovation

We build the separating walls and floors to a tested detail from the approved drawings and leave access for the sound test, so if a test does fail the remedial work stays limited. You get a written quotation after a site visit, a programme with each inspection dated, and a founder with more than thirty years of hands-on building work. Electrics are certified by a registered electrician, and the sound test and building control sign-off are booked into the handover.

• Free, no-obligation quotations
• Each flat's new electrics signed off by a registered electrician for Part P
• Full plans application to building control, never a building notice

Reviewed jobs near Hackney

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

• Install new dishwasher, Stoke Newington, 24 May 2021 (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.