Single and double storey extensions in Streatham. Trusted, professional, 30+ years' hands-on experience.
GS Renovation designs and builds extensions across Streatham, adapting the bay-fronted Victorian and Edwardian terraces of SW16 for modern family living. With over 30 years in Lambeth, we handle everything from the side-return infill to the double-storey rear, taking your project from groundworks through steelwork to full fit-out.

The most popular Streatham extension fills in the side return, the narrow strip beside the rear closet wing, and pushes out to the rear to create a wide open-plan kitchen-diner. Because the original rear wall carries the floors and roof above, we install a steel beam sized by the engineer and infill the side return with a glazed roof or lantern to bring light deep into the plan.
We start with the groundworks, digging and pouring foundations to the depth building control requires, mindful of nearby trees and the clay subsoil common across South London. From there we build the walls, set the steel, close in the roof and complete the fit-out, keeping the works tidy while you live around them in your SW16 home.
Many single-storey rear extensions on Streatham terraces fall under permitted development, meaning no full planning application is needed, though we always confirm the property is not in a conservation area or subject to an Article 4 direction before relying on it. Larger schemes, double-storey rears and wrap-arounds usually need a full planning application to Lambeth Council, and we prepare the drawings and manage that submission for you.
Whether the route is permitted development or planning permission, the structural work always needs building regulations approval and sign-off, which is separate from planning. Where the extension sits against or excavates near a party wall, notices under the Party Wall Act apply too. We map out every consent your specific SW16 property needs so there are no surprises once the build is underway.
Streatham homeowners choose GS Renovation because one team runs the whole extension, from foundations and steel to roofing and the final finish. We advise honestly on whether your scheme is permitted development or needs a Lambeth planning application, handle building control and party wall matters, and draw on 30+ years of building on SW16 terraces.
It's the second time I have hired George and he has been absolutely professional and the work he did resembles perfectly what I had in mind. Being an…
Really happy with the quality of remedial works carried out by George in putting other previous tradesman work right. He was very helpful, honest and…
George is a very hard working builder, and has done a fantastic job on replacing my Bathroom. His attention to detail was great and I wouldn't…
FAQ
Set aside the structural element, the finishing trades and the approvals as three separate amounts. That is how the house extensions quotation for a Streatham home is laid out, and it is why the SW16 survey happens before any figure is discussed. The engineer's fee, where house extensions need a design, is shown rather than buried. Ask GS Renovation on 07472 424 226 for the current position in Lambeth. The survey at the SW16 property is free, in Streatham and across Lambeth. 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 tell you exactly, once we have seen the house. Guessing a house extensions duration for a Streatham property without a survey helps nobody, and the SW16 visit is free. GS Renovation then issues a staged programme including the Lambeth Council inspection dates and the drying time that cannot be rushed. That is the version to plan a Lambeth household around. Ring 07472 424 226 and we will describe how a similar SW16 job ran in Lambeth.
Properly, because in a terrace it affects everyone. GS Renovation agrees working hours with a Streatham household before house extensions begins, dust-seals the SW16 work area, and leaves the site clean each evening. Waste is removed rather than allowed to accumulate. Full insurance and a named manager on the Lambeth site cover the rest. Ring 07472 424 226 and we will explain the site rules. Full insurance covers every SW16 project we run across Lambeth.
Many single-storey rear extensions in Streatham fall under permitted development, but side returns, double-storey extensions and work in conservation areas usually need full permission. We assess your SW16 property and manage both the Lambeth Council application and building control.
More opening up than a modern house requires. Before house extensions proceeds at an SW16 property, GS Renovation confirms what is actually carrying load, because Edwardian bay-fronted houses with generous ceiling heights and long rear gardens rarely match their drawings. Services and drainage are checked at the same time. The Streatham quotation then reflects what is there rather than what was assumed in Lambeth. Ask on 07472 424 226 what house extensions normally involves opening up at an SW16 address in Streatham before anything else.
It depends on the property. Many single-storey rear extensions on Streatham terraces are permitted development, but this is removed in conservation areas or under an Article 4 direction, and larger, double-storey or wrap-around schemes usually need a full application to Lambeth Council. We check your SW16 address first, then advise the correct route. Either way, the structure needs separate building regulations sign-off.
Almost certainly, and we will confirm it in a minute rather than leave you guessing. GS Renovation covers Streatham and the SW16 area for house extensions, along with neighbouring parts of Lambeth. Ring 07472 424 226 or email info@gsrenovationltd.co.uk with the SW16 address before you spend time on drawings. There is no charge for asking, and none for the survey either. We would rather tell you straight away than quote and hope. Small jobs are welcome at SW16 too.
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 Streatham. Explore what else we do locally:
Same Service, Nearby Areas
We carry out house extensions across Streatham and the surrounding areas. Explore a nearby location:
Free, no-obligation quote for house extensions in Streatham. Rated 4.9 from 31 reviews on MyBuilder, fully insured, and building control handled for you.