Flat Conversions Hammersmith and Fulham

Flat conversion work in Hammersmith and Fulham starts with the size of the house. Local Plan Policy HO2 permits converting a dwelling into two or more flats only where the original dwelling's net floor area is more than 120m2, and at least 50% of the new units must have two or more bedrooms. So the tall Victorian and Edwardian houses are the candidates, and the plan is shaped by bedroom mix before a single partition is drawn. We build the approved scheme, from structure and fire separation to the finished flats.

In Hammersmith and Fulham, 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 Hammersmith and Fulham: 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 Hammersmith and Fulham houses qualify for conversion into flats

A house in Hammersmith and Fulham qualifies for conversion only if it is big enough. Policy HO2 (Housing Conversion and Retention) sets the test at an original net floor area of more than 120m2. It also asks that at least 50% of the new units have two or more bedrooms, and that family housing has access to garden or amenity space. A layout that meets both tests often puts the family flat on the ground floor with the garden, and the smaller units above.

Measure before you commit. Splitting a house into flats is development in its own right, so it needs planning permission whatever the size, and the owner or their designer applies. HO2 counts the original floor area, so a later rear addition may not help the numbers the way you expect. Houses make up 23% of the borough's homes, so a qualifying house is a limited asset, and the drawings need to get the mix right first time. We price from the designer's scheme and point out early where a structural or drainage issue could force a layout change.

Housing in Hammersmith and Fulham

Around 95,080 homes make up Hammersmith and Fulham on the valuation list; 77% are flats and 23% houses, and 56% date from before 1919, 9% from between the wars and 34% from after 1945. Where most homes are flats, a flat in Hammersmith and Fulham 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 for Hammersmith and Fulham conversions

Every new flat in a Hammersmith and Fulham conversion has to meet space standards. Policy HO11 (Detailed Residential Standards) applies floor area and room size standards, including the Nationally Described Space Standards, to conversions and changes of use. London Plan Policy D6 then sets the room minimums: a one-bedspace single bedroom needs at least 7.5 square metres and a width of 2.15m, and a two-bedspace double or twin bedroom needs at least 11.5 square metres. Space standards sit within the planning system, not the building regulations, so a plan that misses them by a small margin is a planning problem. We set out partitions from the drawings with a tape before any stud goes up.

Ceiling height is where period houses bite. Policy D6 sets a minimum floor to ceiling height of 2.5m for at least 75 per cent of each dwelling's Gross Internal Area. Tall ground and first floors in older houses usually clear that, while top floors under a pitched roof and rear additions with low ceilings may not. Adding acoustic ceilings and fire linings also takes height, so we check the finished figure against the drawings before any ceiling is dropped, and flag rooms that sit close to the line.

Fire separation and sound insulation between the new flats

The floors and walls between flats carry the hardest technical work in a Hammersmith and Fulham conversion. Part B of the Building Regulations needs each flat to be a separate fire compartment, with a protected stair, fire doors to each flat entrance, and fire stopping wherever pipes and cables pass through. In a period house that can mean replacing the lath ceilings over habitable rooms with fire rated boards and filling the joist voids where the specification calls for it.

Sound is the other half. Approved Document E sets lower performance for flats formed by material change of use than for new build: 43 dB airborne for walls, floors and stairs, and 64 dB maximum impact for floors and stairs. Old timber floors rarely reach that without work, so we add independent ceilings, acoustic insulation and resilient layers to the specification and allow for pre-completion sound testing. Getting it right before plastering avoids opening up finished rooms later.

Services, addresses, party walls and CIL for Hammersmith and Fulham conversions

Each new flat needs its own services and its own identity. That means a separate electricity supply and meter, water and heating for each unit, and new drainage connections, often including a new soil stack. The flats also need addresses from the council's street naming and numbering service before the utilities will set up supplies, so that application goes in early. In Hammersmith and Fulham the council's planning guidance strongly recommends following the Party Wall Act 1996 before building work affecting party walls, and the building owner serves any notices.

Two more checks sit with the owner. A conversion that creates a new dwelling is liable for CIL in Hammersmith and Fulham, where the charging schedule became effective on 1 September 2015, so your designer or planning agent confirms liability and any relief before work starts. The reverse job also comes up. Some buyers of a converted period house want two flats turned back into one house, which means removing extra kitchens, meters and fire lobbies and reopening the stair. Ask your designer whether that loss of a flat needs planning permission first.

• Protected escape stairs and fire-rated flat entrance doors
• Fire detection in every flat and the common hall, laid out to the fire strategy
• House to flat conversions into two or more self-contained units

VOA Council Tax stock of properties, March 2025, for all 25 statistical areas in Hammersmith and Fulham. Counts rounded by the VOA.

Before committing to flat conversions in Hammersmith and Fulham, it is worth looking at structural alterations in Hammersmith and Fulham, our Hammersmith and Fulham area guide, building control sign-off for a conversion, renovations across London, flat conversions across London and Adding Value to a London Flat.

Trusted Flat Conversions in Hammersmith and Fulham

A conversion has more hidden work than it looks: new drainage stacks, separate services and meters for each flat, steel where walls move, and the fire and sound layers that building control checks and a sound test measures. We run the whole build in one programme and give you a written quotation after a visit. Steel is built to a structural engineer's design, a registered electrician certifies the electrics, a Gas Safe engineer does the gas work, and you receive a full set of certificates for the sale or letting of each flat.

• Each flat numbered and supplied before the keys are handed over
• Photographs kept at each stage for your records
• Mains-wired, interlinked smoke and heat alarms to the approved fire strategy

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.