House Extensions Wallington
Single storey rear and double storey extensions in Wallington, planning, structure and build under one contract.
- Rated 4.9 from 31 reviews on MyBuilder
- Single-storey rear extension from £40,000
- Free site survey, itemised quote
GS Renovation extends homes across Wallington, from the Edwardian family houses near Beddington Park to the interwar and post-war semis of SM6. Whether you want a rear kitchen extension, a side-return infill or a double-storey addition, we handle the foundations, the steelwork, the roof and the full fit-out as one project.
In Wallington, a single-storey rear extension typically starts from £40,000, or £2,000 to £2,800 per m² (indicative London ranges, Architecture for London, Resi, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in Wallington: the structural engineer we appoint designs the structure, we build it, and building control signs it off.
Price guide
| Work | Indicative London range |
|---|---|
| Single-storey rear extension | from £40,000 |
| Rear extension, per m² | £2,000 to £2,800 |
| Side return, per m² | £2,400 to £3,200 |
| Wraparound, per m² | £2,400 to £3,200 |
| Double storey, per m² | £1,800 to £2,600 |
| Basement extension | see the basement page |
Indicative London ranges (Architecture for London, Resi, MyBuilder and Checkatrade, 2026), not a quotation. Prices checked September 2026. Full breakdown: Extension Costs & Planning.
Quick estimate for Wallington
Wallington range: choose above
Rear, kitchen and side-return extensions in Wallington
Most of the extensions we are asked about in Wallington are rear kitchen extensions. On a semi, a single storey addition across the back, up to 3 metres deep under permitted development or up to 6 metres through the prior approval route, brings the kitchen into the new space and turns the old back room into the dining end. On a terrace, the side return beside the rear closet wing is often wasted space, and filling it in and extending across the back of the house creates the wide, open kitchen-diner most families want. We tie the new structure into the existing rear wall, insert a steel beam where the old external wall comes out, and match the brickwork so the extension sits naturally against the existing house.
Every extension starts below ground. We dig and pour foundations to the depth building control requires, allowing for any nearby trees around Wallington's leafier roads, then build up in blockwork and brick. Steel beams carry the openings and the roof, which we finish as a pitched or flat structure with rooflights to bring daylight deep into the plan. Drainage, insulation and the internal fit-out all follow, managed by the same team from start to finish.
Housing in Wallington
About 7,270 homes are listed for Wallington, and the mix is 55% houses to 45% flats, with 42% built after 1945, 28% in 1919 to 1939 and 30% earlier. 31% of homes here are semi-detached; a rear extension on a semi in Wallington digs beside the attached neighbour, so one party wall notice is usual.
Article 4, special local character and extension routes in Wallington
Before assuming a Wallington rear extension is permitted development, check the address. Sutton lists an Article 4 Direction, confirmed in 1984, under which the properties it covers need a planning application for extensions, dormer windows and other roof alterations. In the Wallington Green Conservation Area, side and two-storey rear extensions lose permitted development, though a single-storey rear extension keeps it unless an Article 4 says otherwise. Sutton's Local Plan also states that the district centre is surrounded by no less than four Areas of Special Local Character. That local designation does not remove permitted development, but it is weighed when an application is needed.
There are two ways to get a firm answer. Sutton explains that a Lawful Development Certificate application is judged purely against legislation and does not require neighbours to be notified, so it confirms permitted development without a public consultation. Where the scheme needs planning, Sutton runs a paid pre-application advice service with a householder category. Either way, draw the extension with the Design of Residential Extensions document open, since it is one of Sutton's adopted Supplementary Planning Documents and carries weight when an application is decided.
Planning and permitted development in Wallington
Some extensions in Wallington fall under permitted development and do not need a planning application, while others require full permission from Sutton Council. It depends on the size, height and position of what you are building, and whether your property sits in a conservation area or has had permitted development rights removed. We assess your home early, advise which route applies, and coordinate the drawings and the application to the council where planning permission is needed.
Separate from planning, every extension must meet building regulations, and building control inspects the foundations, the steelwork, the insulation and the drainage as the work proceeds. On semis and terraces, a rear or side extension usually sits against a shared boundary, so party wall notices to your neighbours often come into play too; you serve them as the building owner and we give you the drawings they need. We coordinate planning where needed, building control and the party wall programme, so nothing holds the project up.
Double storey extensions in Wallington
Under permitted development a two-storey rear extension can go no more than 3 metres beyond the original rear wall and must stay at least 7 metres from the rear boundary, and in a conservation area it is not permitted development at all. Many gardens are too short for the 7 metre rule, so a double storey extension in Wallington often needs planning permission from Sutton Council. With 37% of homes here semi-detached or detached, the side of the house is often an option too. The Wallington Green Conservation Area was designated in 1971 and covers 3.7 hectares, with a long history dating back to Roman times (council source). Our double storey extension page explains the build, at £1,800 to £2,600 per m² across both floors.
- Building control inspections at foundation, damp course and steel stages
- Planning applications and permitted development assessments
- Brickwork and mortar matched to the existing elevation
VOA Council Tax stock of properties, March 2025, for Wallington North and Wallington South. Counts rounded by the VOA.
The GS Renovation Difference in Wallington
Homeowners across Wallington and the wider SM6 area choose GS Renovation because we take an extension from first drawings to finished room without handing you between contractors. Our founder's 30+ years on the tools means we understand these houses, the local ground and how Sutton Council handles applications. One team, one point of contact, and a build that lasts.
- Free follow-up visit after completion if anything needs attention
- Weathertight shell reached before the fit-out begins
- Permitted development checked before you pay for a planning application
Built a new extension at rear of property. Laid foundations, drainage, raised floor, new roof and completed all fixtures and interior decoration…
George was brilliant. Lovely bloke, very reasonably priced and a perfectionist to boot. He completed our small kitchen renovation with care and great…
Giorgio is an excellent and intelligent workman, and with very reasonable prices! He installed a kitchen extractor fan in a complicated situation…
FAQ
Frequently Asked Questions about House Extensions Wallington
Is the price of house extensions higher in Wallington than elsewhere in South London?
Work on house extensions in Wallington is priced from scope, so it costs no more than the same house in Carshalton, typically £2,000 to £2,800 per m² for a rear extension (indicative). Costs rise in period stock and with awkward access, both checked at SM6. What neither changes is the order of work: the steel into the house is designed before the rear wall comes down. GS Renovation shows each as its own line.
Will my Wallington rear extension need planning permission?
It might not. Many single-storey rear extensions in Wallington fall within permitted development, provided they stay within the size and height limits, but larger, double-storey or wrap-around builds usually need a full application to Sutton Council. Conservation area status also changes things. We check your property first and tell you exactly which route applies before any work begins.
How close to a tree can a Wallington extension be built?
Close enough, if the foundation is designed for it. Tree roots dry out clay soils unevenly, so foundations near trees on Wallington's leafier roads are taken deeper or designed differently, and that includes a neighbour's tree near the boundary. The engineer considers the tree's species, height and distance. Building control then inspects the depth in the open trench before any concrete is poured.
Does a semi-detached Wallington house need party wall notices for a rear extension?
Often. With 37% of Wallington homes semi-detached or detached, the attached side is the one to watch: a rear extension usually runs along that boundary, and a trench there tends to go lower than next door's footings, which calls for a month's notice under the Party Wall Act. A wall built on the line itself needs notice too. On the detached side, or on a detached house, notice is less often needed.
What insulation does a Wallington extension need?
It must meet current Part L standards across walls, floor, roof and glazing. The more glass, the harder the insulation calculation becomes, so the roof and glazing are balanced at design stage. The old rear wall of the house becomes an internal wall once the extension is built, and the opening through it is formed with steel.
What happens to the boiler flue and soil pipe on the rear wall when a Wallington extension goes on?
They usually have to move. A boiler flue cannot discharge into the new room, so a Gas Safe registered engineer relocates it or the boiler. A soil stack on the rear wall is rerouted, keeping the falls required under Part H. Both are planned at design stage because they affect where the extension walls and roof can go.
How does the 40m2 threshold affect Sutton's building control fee for a Wallington extension?
Sutton's charging schedule has one fee for a single storey extension under 40m2 and a higher one for a single storey extension over 40m2, both including VAT. A Wallington kitchen extension that lands just over that size moves into the higher band, so measure the floor area on the drawings before the application goes in. The regularisation fee in each band is higher again, which is the cost of building first and applying later.
When does Sutton issue the completion certificate for a Wallington extension?
Sutton's inspection schedule says a completion certificate follows in 5 working days if the final inspection is OK and installer certificates are received. The installer certificates are what slow it down: electrical, heating and glazing paperwork from each trade. On a Wallington extension, collect them as each trade finishes rather than chasing them after the final visit, so neither the certificate nor a later sale or remortgage is held up.
Can Sutton advise on permitted development before a Wallington extension is drawn up?
Yes. Sutton's pre-application charging schedule includes a category for permitted development or prior approval advice, set at a lower charge than householder development advice. It suits a Wallington owner who wants a rear extension without a full application but is unsure whether the house has lost its rights. Bring measured drawings and photographs of the rear. If a formal answer is needed for a sale or a lender, a Lawful Development Certificate gives one.
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