Single and double storey extensions in Balham. Trusted, professional, 30+ years' hands-on experience.
GS Renovation designs and builds extensions across Balham, working with the bay-fronted Victorian and Edwardian terraces that define SW12. Side-return infills, rear extensions and loft-to-ground reconfigurations are our daily work here. With 30+ years across Wandsworth, we take a Balham extension from foundations and steelwork through to a fully fitted, building control signed-off finish.

Balham's terraces almost all have a narrow side return running alongside the rear closet wing, and infilling it is the classic way to widen a cramped kitchen into a bright kitchen-diner. We dig and pour the foundations, tie the new structure into the existing solid brick wall, install the steel beams that carry the original rear wall and build up with a mix of solid roof and rooflights to pull daylight deep into the plan.
A single-storey rear or wrap-around extension on these plots often falls under permitted development, but not always. Conservation area status, previous additions, the closet wing and how close you build to the boundary can all tip a project into needing a full planning application to Wandsworth Council. We assess your specific house early, advise honestly on which route applies and prepare the drawings either way so there are no surprises.
Where a family needs a bedroom and bathroom as well as more ground-floor space, a double-storey rear extension over the closet wing can transform a Balham terrace. This is bigger structural work, with heavier steel, deeper foundations and a roof that must marry into the existing Victorian roofline, so it almost always requires planning permission from Wandsworth Council rather than falling under permitted development.
Because the flank and rear walls are usually shared with neighbours come into play alongside the building regulations that govern the structure, insulation, drainage and fire safety. We manage the whole chain: engineer, planning drawings, party wall coordination, groundworks, steel, roofing and the full internal fit-out. One accountable team means the Balham extension is delivered to a single standard, on a single programme, from first dig to final decoration.
Balham families choose GS Renovation because we understand exactly how these terraces are built, from the side return to the closet wing to the shared party walls. We advise clearly on permitted development versus a Wandsworth planning application, handle foundations, steel, roofing and fit-out under one roof, and back every job with building control sign-off and 30+ years of local experience.
We loved working with George and Ibrahim and would highly recommend them. They have done splendid job on our new kitchen refurb which including new…
The kitchen has been fitted to the high standard. Saaid was polite, professional, tidy, he pays attention to a little details that make huge…
Really great job done in our bathroom to replace the shower head in the bathtub, and install a shower screen and caddy. We are very happy with the…
FAQ
No. House extensions are priced from scope, so a Balham home is not quoted higher than the same house over in Battersea. Where costs do rise is in period stock and awkward access, both of which are checked at the SW12 property. GS Renovation shows those as separate lines so you can see the reason. The SW12 survey costs nothing and there is no obligation afterwards, in Balham or anywhere in Wandsworth. 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.
Three things, in practice: inspections, materials and late changes. A house extensions project in a Balham home stalls when Wandsworth Council cannot attend before work is concealed, when a specified item has a long lead time, or when the specification changes after the SW12 order is placed. GS Renovation manages the first two and warns you about the third. Nothing about a Wandsworth delay is hidden. The Balham programme names when each Wandsworth decision is needed.
Accountability, mainly. The person who surveys your SW12 property is answerable for what happens on the Balham site, and house extensions are delivered by our own team rather than sold on. GS Renovation is fully insured, coordinates Wandsworth Council building control, and gives you a five year guarantee on installations. The 31 MyBuilder reviews behind our 4.9 rating are public. Ask on 07472 424 226 for Wandsworth addresses to look at. The five year guarantee covers installations at SW12.
For a single-storey rear extension, commonly 3 metres on a terraced or semi-detached house and 4 on a detached one, with a larger allowance available under prior approval. Those rights are withdrawn in conservation areas and where Article 4 applies, so we confirm your SW12 status with Wandsworth Council.
That the making good matters as much as the structure. Reinstating cornice, floors and plaster around house extensions at an SW12 address is where the time goes in two and three-bedroom Victorian terraces, a good many now split into flats, and it is the part cheap quotations leave out. GS Renovation itemises it for your Balham home. Ask any other Wandsworth quotation to do the same. Email info@gsrenovationltd.co.uk and we will explain the making good that house extensions usually needs at an SW12 address.
It depends on the house. Many single-storey rear and side-return extensions in Balham qualify as permitted development, but conservation area status, earlier additions or building close to the boundary can require a full planning application to Wandsworth Council. Double-storey extensions almost always need permission. We assess your specific property first and prepare the right drawings, plus the building regulations submission, whichever route applies.
Ring 07472 424 226 or email info@gsrenovationltd.co.uk with the postcode and you will have an answer today. GS Renovation covers Balham and the SW12 area and the surrounding Wandsworth for house extensions, and we will say straight away if a property falls outside. Nothing is owed for asking, and the survey that follows is free. There is no obligation at any stage. We will suggest someone else if we are not right. The SW12 survey follows at no cost.
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 Balham. Explore what else we do locally:
Same Service, Nearby Areas
We carry out house extensions across Balham and the surrounding areas. Explore a nearby location:
Free, no-obligation quote for house extensions in Balham. Rated 4.9 from 31 reviews on MyBuilder, fully insured, and building control handled for you.