Kitchen Extensions Mayfair

A kitchen extension in Mayfair starts from a small pool of houses: 96% of homes here are flats, 4% are houses and 3% are terraced houses. Where there is a house, the realistic addition is a modest room at the back. Where there is a flat, the kitchen can only grow outwards through a planning application, since extension rights under permitted development belong to houses alone. We build the structure, the drainage and the new kitchen as one programme, working to the consent your designer secures.

In Mayfair, 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 Mayfair: 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.

What a Mayfair house or flat can add for a bigger kitchen

The answer turns on whether you own a house or a flat. Permitted development for extensions covers houses only, so any addition to a Mayfair flat or maisonette needs a planning application. The lease will normally require the landlord's licence to alter as well. Extra kitchen space for a flat can come from a closet wing, a lightwell, an unused yard at lower ground or a reworked internal plan. An internal replan is not development and needs no planning permission, but a building on the statutory list needs heritage consent for it. Each option needs drawings before we can programme the build.

A listed building is the exception: work that affects its character, inside or out, including an extension or taking out a wall or chimney breast, needs listed building consent from Westminster City Council, and doing it without consent is a criminal offence.

With 3% of homes here counted as terraced houses and none as semi-detached or detached, a house owner is working with a narrow plot and neighbours on both sides. That shapes the build as much as the design: materials come through the house or over a front lightwell, and steel often goes in by hand in sections. New work on or against a party wall needs notices under the Party Wall etc. Act, which the building owner serves. We plan deliveries and the order of trades around that single route in and out.

Housing in Mayfair

Roughly 7,560 dwellings sit on the valuation list for the Strand, St James & Mayfair statistical area. 4% are houses and 96% flats, and by age 52% predate 1919, 5% are interwar and 41% post-war. Most homes here are flats, and only a ground floor flat in Mayfair with its own garden can extend its kitchen.

How Mayfair's conservation status keeps the addition modest

It holds down width and height more than anything else. The Mayfair conservation area was first designated in 1969 and has been extended since, and Westminster's conservation guidance says full width rear extensions are generally not acceptable, except in certain circumstances at basement level. The same guidance says an extension must respect the scale and proportions of the existing building and be architecturally subordinate to it. Plan on a part-width room with a roof line kept below the main house, rather than a full-width glass box.

For your kitchen layout that means a narrower footprint, with the length placed where the plan allows. One arrangement that works puts the run of units and the sink along the party wall, with the table or island under the new roof light, so the old back room and the addition read as one space. The planning drawings fix the envelope; the kitchen design inside it can be settled with us while the application is running.

Steel, drainage and glazing where the Mayfair kitchen meets the house

The hard part is the junction, not the new room. Opening the back wall of a Mayfair terrace means a steel beam sized by the structural engineer we appoint, propping while the old masonry comes out, and padstones built into sound brickwork. The drainage often has to be rerouted too, since the sink moves outwards and the old gully can end up under the new floor, so we survey the runs before the slab goes in.

Glazing and roof lights decide how the space feels on a narrow plot with tall neighbours. A roof light over the join lets daylight reach the old back room, and large doors to the yard should be ordered early, as they have long lead times. Where Westminster's District Surveyors are the building control body, a completion certificate is only issued once all fees are paid and the electrical and gas certificates are in, so we collect those as each trade finishes.

Running a small kitchen extension site on a Mayfair street

A job of this size can still follow Westminster's construction code. If your extension falls in the code's Level 4 for small projects, it is expected to keep to the code's principles but needs no formal approval, no monitoring and no fees. For you that means quiet working, dust control and tidy deliveries without a separate approval step, and we brief every trade on those expectations before the first day on site in the street.

Anything placed in the road or on the pavement is different. Scaffolding, construction fencing, a crane or a cherry picker on the highway needs a temporary structure licence from Westminster, so a steel lift or a street-front scaffold goes into the programme with the licence lead time. Where Westminster is the building control body, it also needs your start date on the application form or by email at least 2 days ahead, which we build into the first week of the sequence.

• Party wall process explained, with drawings for your notices
• Building control inspections from footings to completion
• Floor levels matched through the old opening

VOA Council Tax stock of properties, March 2025, for the Strand, St James & Mayfair statistical area, which also covers St James's and the Strand. Counts rounded by the VOA.

Related reading for Mayfair homeowners planning kitchen extensions: kitchen renovation in Mayfair, kitchen extensions across Westminster, a wraparound kitchen-diner, sign-off by building control on a kitchen extension, how we handle kitchen extensions across London and Underfloor Heating Costs.

Why Choose GS Renovation in Mayfair

You get one team for the structure and the kitchen, so the steel, drainage, roof light and units are sequenced by the same people rather than handed between two firms. We price from a site survey and your designer's drawings, set out the programme before you commit, and keep the building control inspections and the certificates in order for completion. Abdelaaziz Saaid, the founder, has spent decades on the tools and plans each stage with that hands-on knowledge.

• Fully insured, with cover in place on every site
• Building control and Part P certificates handed over together at the end
• 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.