Single and double storey extensions in Finchley. Trusted, professional, 30+ years' hands-on experience.
GS Renovation designs and builds extensions across Finchley, where 1930s semi-detached and interwar houses sit on generous suburban plots with room to grow. With more than 30 years of building experience in N3 and across Barnet, we handle the groundworks, the steel, the roof and the full fit-out as one accountable project.

The wide plots typical of Finchley suit generous single storey rear extensions and side infills that fill in the gap alongside the original 1930s footprint. We start with foundations and groundworks suited to the local ground, then bring in steel beams where the back wall is removed to join the extension to the existing house. A well-planned rear extension turns the cramped original kitchen into an open-plan kitchen-diner opening onto the garden.
Double storey and wrap-around extensions are also popular on the larger interwar homes near Hampstead Garden Suburb and towards Mill Hill, adding a bedroom and en-suite above a widened kitchen. We match brickwork and roof pitch to the existing house so the addition reads as part of the original build, and we handle the roof works, windows, insulation and full internal fit-out through to decoration.
Some Finchley extensions fall under permitted development, while others need a full planning application to Barnet Council. It depends on the size, the height, how close you build to the boundary and whether your street or property carries any restrictions. Homes within or near the Hampstead Garden Suburb conservation area face tighter controls. We assess your specific property early and tell you honestly which route applies before any design is finalised.
Whichever route you take, the structural work still needs building regulations approval and inspection, which is separate from planning. Because these are semi-detached and closely spaced houses, excavating foundations near the boundary or building onto the shared wall brings the Party Wall Act into play, so notices go to neighbours in good time. We coordinate planning, building control and party wall matters so nothing stalls the programme.
Finchley homeowners choose GS Renovation because we manage the whole extension, from foundations and steel to the roof and the final coat of paint, with one team answerable for the result. We advise clearly on permitted development versus a Barnet Council planning application, handle party wall notices on your semi, and bring 30+ years of local building to every stage.
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
We price each Finchley project individually, because the cost of house extensions depends on far more than floor area. After a free survey you receive a clear written breakdown with no hidden extras. Call 07472 424 226 or email info@gsrenovationltd.co.uk. 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.
We will give you an honest timescale for house extensions in Finchley after surveying your home. Most projects run on a clear weekly programme, and we tell you up front about any lead times on materials or approvals.
With more than three decades of hands-on trade experience behind us, GS Renovation is a trusted choice for house extensions in Finchley. You get one accountable team, transparent pricing, fully insured tradespeople and genuine aftercare on every project.
Many single-storey rear extensions in Finchley 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 Finchley's homes are 1930s and interwar properties, and we renovate them regularly. We plan each house extensions around their particular characteristics, such as cavity walls, regular original layouts and the generous plots that suit extending, so the result suits the building and meets building control.
It depends on the property. Many single storey rear extensions on Finchley's generous plots fall under permitted development, but larger, double storey or wrap-around builds, and anything near the Hampstead Garden Suburb conservation area, often need a full planning application to Barnet Council. We assess your specific home first and confirm the route. Either way the structural work still needs separate building regulations sign-off.
Absolutely. Our team works right across Finchley and the N3 area and neighbouring parts of North London. Get in touch on 07472 424 226 to check coverage for your address.
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 Finchley. 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 Finchley and the surrounding areas. Explore a nearby location:
Contact GS Renovation today for a free, no-obligation quote for house extensions in Finchley.
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