Flat Conversions Brentford

Flat conversions in Brentford start from a limited pool: 35% of homes in the Brentford wards, whose figures take in Osterley Park, are houses. The candidates for splitting are the Victorian and interwar terraces and larger semis rather than the riverside blocks. Hounslow tests every scheme against Local Plan Policy SC6, which looks for at least 130sqm of net original internal floor area and a family-sized flat on the ground floor. We build the consented scheme, from the separating floors and protected stair to the separate services for each new home.

In Brentford, 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 Brentford: 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.

Testing a Brentford house against Policy SC6 before drawings

The first question for a Brentford conversion is floor area, measured as the house was built. Policy SC6 expects a minimum 130sqm of net original internal floor area for a house to be considered suitable for conversion or subdivision. Hounslow told its 2020-2041 Local Plan examination that the same threshold carries into the emerging policy on managing building conversions. A house that only reaches 130sqm because of a rear extension or added outbuildings will not be supported, so later additions are left out of the sum.

With 19% of Brentford homes terraced houses and 16% semi-detached or detached, the candidates are the bigger houses of each type, and a measured survey of the original rooms answers the question at modest cost. If the house falls short, the money is better spent on it as one home. If it passes, we walk the house with your designer and talk through where partitions, the stair enclosure and the drainage stacks can practically go from a builder's side.

Housing in Brentford

Brentford counts roughly 13,230 homes for Council Tax; 15% are older than 1919, 24% interwar and 61% post-war, with 65% flats and 35% houses. Most homes here are flats, and changing the number of flats in Brentford needs the freeholder and usually planning.

Family flats, space standards and outdoor space in Brentford

Hounslow Policy SC6 requires at least one family-sized unit, two bedrooms for four people or more, at ground floor level in any residential conversion. In a Brentford terrace that normally gives the garden to the ground floor flat and puts smaller flats above, off a shared stair. The Local Plan asks for internal space that complies with the Nationally Described Space Standard, and GOV.UK notes that the standard sits solely within the planning system, not the building regulations.

London Plan Policy D6 adds the detail that shapes each flat in a Brentford conversion. A single bedroom needs at least 7.5 square metres and 2.15m of width, a double or twin at least 11.5 square metres, and at least 75 per cent of each flat needs a floor to ceiling height of 2.5m. Where the borough sets nothing higher, D6 asks for at least 5 square metres of private outdoor space for one or two people. It also favours dual aspect homes, which a front-to-back floor in a terrace can give.

Separating new Brentford flats for fire and sound

A conversion is a material change of use, and each new flat in Brentford has to be separated from its neighbours. Approved Document E sets flats formed this way at a minimum of 43 dB airborne sound insulation for walls, floors and stairs, and 64 dB maximum impact for floors and stairs, confirmed by pre-completion sound testing. For fire, the floors and walls between flats and around the shared stair become fire separating construction, with fire doors onto a protected escape route and interlinked detection.

Hounslow's building control service says a full plans application is usually used for a change of building use, so the drawings are approved before work begins. Hounslow sets a building control charge for converting a single family house into two flats, with a further charge for each additional flat up to six. In a timber-floored Brentford terrace we lift the boards, add absorbent quilt and mass, hang a resilient ceiling below and float a new deck above, then seal every service penetration.

Services, addresses, party walls and de-conversion in Brentford

Each new Brentford flat needs its own services: a separate electricity meter and consumer unit, its own heating and hot water, and its own water supply or submeter. Utility companies need the new addresses before they will connect, and those come from the council's street naming and numbering process, so apply early. Where the work cuts into a party wall with the house next door, the building owner serves notice under the Party Wall Act, and we build to the agreed award.

No permitted development route exists for splitting a Brentford house into flats, and separately, on 4 March 2025, Hounslow confirmed an Article 4 direction removing certain permitted development rights that would result in new dwellings. The London Plan counts residential conversions among the forms of incremental intensification where they result in net additional housing. Going the other way, combining flats back into one house reduces the number of homes, so your designer confirms whether planning permission is needed before any separating work comes out.

• Common hallway, stair and entrance finishes
• Splitting a large flat in two, or joining two flats into one
• Protected escape stairs and fire-rated flat entrance doors

VOA Council Tax stock of properties, March 2025, for Brentford Central, Brentford West & Osterley Park and Brentford East. Counts rounded by the VOA.

Two or three things usually come up alongside flat conversions on a Brentford job: structural alterations in Brentford, flat conversions across Hounslow, builders in London who take on conversions, renovations across London, how we handle flat conversions across London and Central Heating Installation Cost.

The GS Renovation Difference in Brentford

A conversion only works if the sequence is right, and we build it in the order building control needs to see it. We work from your designer's approved drawings and your structural engineer's details, finish the separating floors, walls and protected stair before the kitchens and bathrooms go in, and request inspections as each stage closes, including sound testing before completion. You get a written programme, one point of contact for the trades, and the records your agent needs for the new flats.

• Separate meters, supplies and consumer units arranged for every flat
• Each flat's new electrics signed off by a registered electrician for Part P
• Straight advice on what is and is not worth spending money on

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.