House Extensions Barnes

GS Renovation plans and builds extensions across Barnes, adding space to the bay-fronted Victorian and Edwardian terraces and substantial family homes of SW13. We handle everything from foundations and steelwork to roofing and fit-out, and we advise clearly on whether your project is permitted development or needs planning permission from Richmond Council.

In Barnes, 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 Barnes: the structural engineer we appoint designs the structure, we build it, and building control signs it off.

Side-return and rear extensions in Barnes

The most requested extension in Barnes is a kitchen extension that fills the side return beside the rear closet wing, turning a cramped galley kitchen into an open-plan kitchen-diner running the width of the house. We dig and pour new foundations to suit the ground and any nearby trees, tie the brickwork into the existing Victorian wall, and carry the structure over on steel. A glazed roof or roof lantern brings light into what was a dark middle room.

Many single-storey rear and side-return extensions on Barnes terraces fall under permitted development, but this is never guaranteed. Size limits, conservation area status, earlier extensions and the specific property all affect it, and near the Thames flood risk shapes the floor levels and drainage, so some schemes need a full planning application to Richmond Council. We check the position for you, prepare the drawings, and manage the submission, whichever route your Barnes home takes.

Housing in Barnes

Take the 9,740 or so homes the valuation list gives Barnes: 48% flats, 52% houses, 51% from before 1919, 17% interwar and 31% post-war. 33% of homes here are terraced; a rear extension on a terrace in Barnes digs foundations close to both neighbours, so notices to both are normal.

Floor area, fee bands and consent for a Barnes extension

Richmond's building control charges for an extension change at 40 square metres of floor area, with a separate band for an extension over 40 and under 60 square metres. On a Barnes house that line is worth knowing before the design settles, because a scheme drawn just over it moves into the higher band. On a Full Plans application for an extension under 40 square metres the charge is split into a plan fee and an inspection charge, so part relates to checking the drawings and part to the site visits that follow.

Planning is the other gate. In Richmond conservation areas, front and side extensions of one storey or more and two storey rear extensions are among works needing planning permission. Barnes Green conservation area number 1 was designated on 14.01.1969, so check the boundary before assuming permitted development. A single-storey rear extension can still be permitted development there unless an Article 4 Direction removes it. Richmond's householder pre-application advice does not include a meeting with a planning officer, so the drawings have to explain the scheme on their own.

Double-storey extensions on Barnes family homes

On the larger family homes of SW13, a double-storey rear extension adds a bigger kitchen below and a bedroom or en-suite above in one build. We match the foundations and brickwork to the existing house, install the steel to carry the new floor and roof, and tie the roofline in so the addition looks original to the property. This suits families staying in Barnes who need more room without leaving SW13.

A two-storey extension almost always needs planning permission from Richmond Council rather than falling under permitted development, and where it sits on a shared boundary the Party Wall Act applies too, with notices you serve as building owner. We coordinate the planning drawings and the engineer's structural design together, then build the shell, weatherproof it, and complete the full fit-out. From dig to decoration, one Barnes team stays accountable for the whole project.

Kitchen extensions in Barnes

63% of the houses in Barnes are terraced. On a terrace the kitchen extension is built out from the back, into the side return where the house has one or across the full rear width, and a steel beam takes the old back wall so the kitchen and the new room become one space. The fit-out is priced on its own page, kitchen renovation in Barnes; the build figures are in the table above.

• Trial holes to set foundation depth near drains and trees
• Flat and pitched roofs with rooflights or lanterns
• Planning applications and permitted development assessments

VOA Council Tax stock of properties, March 2025, for North Barnes and Mortlake & South Barnes. Counts rounded by the VOA.

If you are weighing up house extensions in Barnes, it may help to read RSJ and steel beam installation in Barnes, house extensions across Richmond upon Thames, wraparound extensions, garage conversions in London, house extensions across London and Party Wall Act Explained.

Why Barnes Homeowners Choose GS Renovation

Families in Barnes choose GS Renovation because we deliver the whole extension under one roof, from groundworks and steel to planning drawings and the final coat of paint. We know how SW13 terraces and family homes are built, we handle Richmond Council submissions and give you the drawings for the party wall notices you serve, and our founder's 30+ years of experience means fewer surprises and a build that adds real value.

• Permitted development checked before you pay for a planning application
• Photographs kept at each stage for your records
• Insulation and thermal detailing to current regulations

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.