Single and double storey extensions in Mayfair. Trusted, professional, 30+ years' hands-on experience.
GS Renovation builds house extensions across Mayfair and the wider W1 district, adding space to Georgian and Regency townhouses close to Hyde Park and the West End. With more than 30 years of experience, we handle groundworks, steel, roofing and fit-out, and guide you through Westminster City Council's planning and conservation requirements.

Plots in Mayfair are generally tight and hemmed in by neighbouring townhouses, so extensions here tend to be modest rear or side-return additions, lower-ground enlargements or roof-level works rather than sprawling ground-floor builds. We assess the foundations, dig and underpin where the party wall and existing structure demand it, and tie new steel into the original brickwork so the extension carries its loads correctly and safely.
Because much of Mayfair is listed or falls within a Westminster conservation area, permitted development rights are usually restricted or removed altogether. That means most extensions here need a full planning application to the council, and often listed building consent as well, rather than proceeding under permitted development. We advise honestly on which route your property qualifies for before any drawings are commissioned, so there are no surprises later in the process.
A typical Mayfair extension project runs from foundations and drainage through steel beams, roofing and a complete internal fit-out, all managed by one team. We match new brick and stone to the period elevation, replicate cornices and joinery inside, and detail the roof to suit the building's proportions. Where a rear wall is shared with an adjoining home, the Party Wall Act applies and we serve notices before any excavation begins.
Working in W1 means coordinating deliveries and skips on busy Westminster streets near Oxford Street and the West End, so we plan logistics tightly to keep disruption to your neighbours low. From the first structural survey to the final coat of paint, we sequence the trades so your extended kitchen-diner or additional bedroom is delivered as a single, accountable contract rather than a string of separate jobs.
Mayfair extensions are constrained by tight plots, listed status and strict Westminster planning, so experience matters. GS Renovation manages the planning route, party wall notices, structural steel and full fit-out under one roof, matching new work to the period fabric. With 30+ years across W1, we deliver additional space that respects the character of your home and the conservation area around it.
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great attention to detail. I've already recommended him to others.
Splendid job on our new kitchen refurb, including new flooring, moving the services, installing RSJ and preparing space for new back doors… George was always friendly, communicative and has an excellent attention to detail, ensuring everything is finished to a high standard.
Giorgio is an excellent and intelligent workman, and with very reasonable prices!… He paid a lot of attention to detail that is not common at all, and the final result was immaculate. Highly recommended!
FAQ
Pricing house extensions in Mayfair comes down to the size of the job, the specification you choose and the condition of the property. Rather than guess, we survey and give you a fixed, itemised quote you can rely on. Call 07472 424 226. As a rough guide, house extensions in London typically starts from roughly £40,000 for a single-storey rear extension and rises with size and specification (indicative London ranges, MyBuilder and Checkatrade, 2026). Your figure depends on the size, specification and condition of the property, which is why we survey before quoting.
Timescales for house extensions in Mayfair vary with the size and complexity of the job. After our survey we give you a realistic schedule and keep you updated at every stage of the project.
Mayfair homeowners choose GS Renovation for reliability and quality. We are fully insured, building control compliant where needed, and bring over 30 years of hands-on experience to every house extensions project, with a single point of contact throughout.
Many single-storey rear extensions in Mayfair fall under permitted development, but side returns, double-storey extensions and work in conservation areas usually need full planning permission. We assess your property and manage both the planning application and building control.
Yes. A large share of Mayfair's homes are period, Georgian and listed properties, and we renovate them regularly. We plan each house extensions around their particular characteristics, such as conservation and listed-building rules, solid walls and original period features, so the result suits the building and meets building control.
Usually not. Because most of Mayfair is listed or within a Westminster conservation area, permitted development rights are commonly restricted or removed, so a full planning application to Westminster City Council is normally required, along with listed building consent for a listed property. We assess your specific address first and advise on the correct route before any design work starts.
Yes. We work throughout Mayfair and the W1 area, as well as the surrounding parts of Central London. Contact us on 07472 424 226 to confirm we cover your street.
Every Service, One Team
The same trusted team, 30+ years' hands-on experience and free, no-obligation quotes apply to every GS Renovation service in Mayfair. Explore what else we do locally:
Steel beam installation, RSJ and structural alterations.
Safe load-bearing wall removal with steel beam support.
Structural alterations, new openings and steel support.
Chimney breast removal with gallows bracket or beam support.
Open-plan kitchen, diner and living conversions.
Full refurbishments and whole-house renovations.
Bespoke kitchen design and installation.
Luxury bathroom and wet-room refurbishment.
Same Service, Nearby Areas
We carry out house extensions across Mayfair and the surrounding areas. Explore a nearby location:
Contact GS Renovation today for a free, no-obligation quote for house extensions in Mayfair.
Get Your Free Quote