Single and double storey extensions in Stanmore. Trusted, professional, 30+ years' hands-on experience.
GS Renovation designs and builds extensions on Stanmore's interwar houses, the substantial detached and semi-detached homes that sit on the generous plots typical of HA7. Over more than 30 years across Harrow and North West London, we have taken projects from foundations through steelwork to a finished, fitted-out space that suits the character of the area.

The wide plots around Stanmore lend themselves to rear and side-return extensions, and often a wrap-around that combines both to create a large open living and dining space. Because 1930s houses were built with a defined internal layout, opening up the rear usually means a steel beam sized by a structural engineer and signed off by building control. We handle the foundations and groundworks first, then the superstructure, the roof and the glazing that brings light deep into the plan.
Double storey extensions are also common on Stanmore's larger semis and detached homes, adding a bedroom or en-suite above the new ground floor room. We match brickwork and rooflines to the existing house so the addition reads as part of the original rather than a bolt-on. Every extension is built to current building regulations, with insulation, drainage and structural details all inspected and approved as the work progresses.
Not every extension needs a full planning application. Many single storey rear extensions on Stanmore houses fall under permitted development, provided they stay within the limits on depth, height and materials. Others, particularly larger, double storey or wrap-around schemes, do need planning permission from Harrow Council. We assess your specific property and tell you which route applies before you commit, so there are no surprises once the design is agreed.
Permitted development still requires building regulations approval, and the two things are separate. We prepare the drawings, submit to Harrow Council where planning is needed and manage the building control inspections throughout. Where the extension sits close to or on the party wall shared with a neighbouring Stanmore home, we also serve the necessary party wall notices. One team carries the project from first sketch to the final decorated, fitted-out room.
Stanmore homeowners choose GS Renovation because we manage the whole extension under one roof, from the engineer's steel to the plaster finish. We tell you honestly whether your scheme is permitted development or needs a Harrow Council application, handle party wall matters and keep every stage within building regulations. With 30+ years in HA7, we build additions that last.
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
There is no fixed price for house extensions in Stanmore, because so much depends on your property and what you want to achieve. We survey first, then provide a transparent written quotation. Contact GS Renovation on 07472 424 226 for a free estimate. 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.
A straightforward Stanmore project can be done in a couple of weeks, while a larger house extensions with structural work runs longer. We set out a realistic, stage-by-stage programme before we begin so there are no surprises.
Stanmore 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 Stanmore 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 Stanmore'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 and the size of the extension. Many single storey rear extensions on Stanmore houses are permitted development if they stay within the size limits, while double storey and wrap-around schemes usually need planning permission from Harrow Council. We assess your home and confirm the route before design work begins. Either way, building regulations approval is still required.
We cover the whole of Stanmore and the HA7 area and the surrounding North West London. If you are nearby and not sure, just call 07472 424 226 and we will tell you straight away.
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 Stanmore. 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 Stanmore and the surrounding areas. Explore a nearby location:
Contact GS Renovation today for a free, no-obligation quote for house extensions in Stanmore.
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