Kitchen Extensions Brentford

A kitchen extension in Brentford starts with what you own. 65% of homes here are flats and 35% are houses, and householder permitted development for extensions applies to houses only, not to flats and maisonettes. For Brentford's terraces and semis, the question is how far back the new kitchen can go under Hounslow's depth limits, where the drains run, and how the steel meets the old back wall. We build the shell and fit the kitchen in one programme.

In Brentford, a rear kitchen extension of about 30 square metres typically costs £45,000 to £97,500 excluding VAT, or £60,000 to £100,000 for a side return (indicative London ranges, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Brentford: the structural engineer we appoint designs the foundations and steel, we build the room and fit the kitchen, and a registered electrician certifies the electrics.

Which kitchen extension suits a Brentford terrace or semi

A Brentford terrace with a rear outrigger suits a side return infill beside it, and a semi suits a full width rear or wraparound. 19% of homes here are terraced houses and 16% are semi-detached or detached, so the house type decides the shape before the budget does. On a terrace the narrow side passage becomes floor, and the long wall along the neighbour's boundary becomes the thing to design around. On a semi you have more width to play with and a side to wrap round.

That choice then drives the rest of the programme. An infill means building on or against a shared boundary wall, with a party wall matter for the owner to deal with before we start. A wraparound on a semi means two new walls meeting at a corner, a longer steel run and more roof to drain. We price the shape you choose, and we tell you early which parts of the house need opening up to find out what is there.

Housing in Brentford

Brentford's housing, as the Council Tax list records it, is about 13,230 homes: 35% houses, 65% flats, with 15% pre-1919, 24% interwar and 61% built since 1945. Most homes here are flats, and only a ground floor flat in Brentford with its own garden can extend its kitchen.

How deep Hounslow lets a Brentford kitchen extension go

The depth depends on the house type: Hounslow's residential extension guidelines set maximum single storey rear depths of 3.05m for a terrace, 3.65m for a semi and 4.25m for a detached house. Since 14 May 2024 the council's newer design codes document has replaced the Residential Extensions Guidelines SPD (2017). Your designer should check the drawing against the current codes as well as the depth table before it is submitted.

For a Brentford infill beside an outrigger that goes past those depths, the guidance keeps the eaves along the neighbour's side to a maximum of two metres, with the roof slope held at 45 degrees or shallower. That is a real constraint on a kitchen. A low eave on the neighbour's side pushes you towards a sloping glazed roof or roof lights along the boundary, and the steel ridge beam has to sit lower than many people picture. We build to whichever drawing gets consent.

Permitted development and designated land around Brentford

Some Brentford houses can extend without a planning application, and some cannot. Under national permitted development rules, a single storey rear extension cannot extend more than four metres beyond the original rear wall of a detached house or three metres for any other house. The word original matters: an earlier outrigger or lean-to may already have used part of that allowance, so the owner's designer measures from the original house, not from a later addition.

Designated land changes the picture. Under permitted development rules, all side extensions on Article 2(3) land, such as a conservation area, need householder planning permission. Brentford's include The Butts, designated in 1968, and St Paul's Brentford, first designated in 1989 and enlarged in 2001. If your house sits in a conservation area, a side return infill is a planning application, and the programme should allow for the decision before we order steel.

Drains, steel and building control on a Brentford kitchen build

The drain run behind a Brentford terrace can decide the building control route. If Hounslow is your building control body and the new kitchen sits on top of a public sewer, or comes within 3m of one, Hounslow will not accept a building notice and wants full plans instead. A shared run can sit behind a row of terraced houses, so we look for manholes and inspection chambers on the first visit and flag it before the drawings are finished. A build over agreement with the water company may also be needed.

Once the route is set, the kitchen goes in as part of the same programme. We dig and pour the foundations, raise the walls, then the steel the structural engineer we appoint has sized goes in to open the old back wall. The roof, glazing and roof lights make it weathertight, and after that the first fix services, plaster, flooring and the kitchen itself follow on without handing over between two firms.

• Hob gas supply altered by a Gas Safe registered engineer
• Kitchen-diner layouts planned before the foundations
• Floor levels matched through the old opening

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

Related reading for Brentford homeowners planning kitchen extensions: kitchen renovation in Brentford, kitchen extensions across Hounslow, a wraparound kitchen-diner, how building control inspects an extension, kitchen extensions across London and Underfloor Heating Costs.

Why Choose GS Renovation in Brentford

You get one team from the first dig to the last cupboard door. We price from the drawings that carry the consent, so the shape you pay for is the shape that was approved. We plan the steel, glazing and kitchen deliveries as one sequence, so the room is not left as a shell waiting for a second firm. The owner's designer handles planning; we build to the approved drawings and tell you each week what has been done and what comes next.

• One point of contact from first survey to handover
• Drains surveyed by camera before the footprint is fixed
• Old kitchen kept in use until the new shell is weathertight

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.