Single and double storey extensions in Isleworth. Trusted, professional, 30+ years' hands-on experience.
Isleworth's TW7 terraces, with their long rear gardens, side returns and closet wings, are ideal candidates for extending. GS Renovation designs and builds single and double storey, rear, side-return and wrap-around extensions across the neighbourhood, bringing over 30 years of building experience in Hounslow borough. We manage foundations, steelwork, roofing, party wall matters and the full fit-out.

The side return, that narrow strip of land beside the rear closet wing, is often wasted on Isleworth terraces. Filling it in widens a cramped galley kitchen into a bright open-plan space, usually combined with removing the wall to the closet wing on a steel beam. We dig new foundations to the required depth, tie the new structure to the existing brickwork, and open the roof up with rooflights for extra daylight.
Many single storey rear and side-return extensions fall under permitted development, but this is not guaranteed. If your Isleworth home sits within a conservation area, is a flat, or has already been extended, you may need a full planning application to Hounslow Council. We assess your property first, advise on the likely route, and handle the drawings and submissions, whether that means a lawful development certificate or a householder planning application.
Where the plot allows, a double storey rear extension adds a larger kitchen-diner below and an extra bedroom or en-suite above, making real use of Isleworth's generous garden depths. These schemes are more likely to need full planning permission from Hounslow Council, and we factor that into the timeline from the outset. Deeper foundations, heavier steelwork and careful tying into the existing roof and party wall all demand experienced hands.
Because these extensions build up against or across the boundary shared with the adjoining terrace, the Party Wall Act nearly always applies, and we serve notices early to avoid delays. Building regulations govern the structure, insulation, fire safety and drainage regardless of the planning route. We coordinate the engineer, the party wall surveyor if needed and building control, then complete the full fit-out so you move straight into a finished, warm and watertight space.
With Osterley Park and Syon Park on the doorstep, Isleworth homeowners want extensions that respect the character of their period homes. GS Renovation handles design, planning submissions to Hounslow Council, structure and finish as one accountable job. Over 30 years in TW7 means we know which schemes gain permitted development rights and which need planning, so there are no costly surprises.
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
Every Isleworth project is priced on its own merits, as the cost of house extensions varies with the size, specification and condition of the home. We give a clear, itemised quote up front with no obligation. Call 07472 424 226 for an estimate tailored to your property. 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.
How long house extensions takes in Isleworth depends on the size of the job, but we always agree a programme before starting and stick to it, keeping you informed from the first day to the last.
With more than three decades of hands-on trade experience behind us, GS Renovation is a trusted choice for house extensions in Isleworth. You get one accountable team, transparent pricing, fully insured tradespeople and genuine aftercare on every project.
Many single-storey rear extensions in Isleworth 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 Isleworth's homes are Victorian and Edwardian terraced properties, and we renovate them regularly. We plan each house extensions around their particular characteristics, such as solid brick walls, rear closet wings, side returns and original period features, so the result suits the building and meets building control.
It depends on the property. Many single storey rear and side-return extensions in Isleworth are permitted development, needing only building regulations approval. However, flats, homes in conservation areas, and properties that have already been extended often require a full planning application to Hounslow Council. Double storey extensions usually do too. We check your specific situation before any work is priced or drawn.
We cover the whole of Isleworth and the TW7 area and the surrounding 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 Isleworth. 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 Isleworth and the surrounding areas. Explore a nearby location:
Contact GS Renovation today for a free, no-obligation quote for house extensions in Isleworth.
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