House Extensions Croydon

GS Renovation builds extensions across Croydon, from the wide 1930s semis in Coulsdon and Purley to the Victorian and Edwardian houses around Addiscombe. We handle the groundworks, the steels, the roof and the full fit-out as one project.

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

Rear and side-return extensions in Croydon

The generous plots typical of Croydon's 1930s suburbs lend themselves to substantial extensions. A single-storey rear extension opens the kitchen onto the garden, while a side-return or wrap-around fills the gap alongside a 1930s semi to create a broad open-plan kitchen-diner. We dig and lay the foundations, build the walls, install the steel beams over the openings and tie the new roof into the existing house.

Whether your project is permitted development or needs a full planning application depends on the property, its size and whether it has been extended before. Many Croydon single-storey rear extensions fall under permitted development, including in a conservation area, but larger, two-storey or front schemes, side extensions in a conservation area, and anything where an Article 4 direction applies need permission from Croydon Council. Flats have no householder permitted development at all. We assess yours honestly and handle the application where one is required.

Housing in Croydon

For Croydon the Council Tax list gives about 168,270 homes; by type 44% flats and 56% houses, by age 48% post-war, 24% interwar and 28% older than 1919. 28% of homes here are terraced; a rear extension on a terrace in Croydon digs foundations close to both neighbours, so notices to both are normal.

Building notice or full plans for a Croydon extension

Croydon says a building notice can also be submitted when building an extension, which lets work start sooner. The exception matters behind the house: anything over, or within 3 metres of, a public sewer has to go in as a full plans application instead. Behind Croydon terraces and semis the pipe serving several houses may cross the gardens, so a rear extension can land close to it. Get the sewer map and a camera survey before choosing the route, because finding the pipe after the notice has gone in means starting the paperwork again.

Two more Croydon points shape the budget and the design. Croydon states that CIL is not charged on extensions or other home adaptations, so a householder extension does not carry the levy. In a conservation area the design brief tightens: Croydon's conservation guidance SPD says two storey rear extensions are generally unlikely to be considered acceptable, and planning permission is needed there for side extensions and some rear extensions. If the house sits in a conservation area, draw the single storey version first and test the larger one at pre-application.

Double-storey extensions on Croydon plots

The deeper gardens found across Purley, Coulsdon and the roads around Lloyd Park often suit a double-storey extension that adds a larger kitchen below and an extra bedroom or en-suite above. These schemes almost always need planning permission from Croydon Council, plus full building regulations approval for the foundations, the steel frame and the roof structure, which we manage from drawings through to completion.

Where the extension meets the boundary with a neighbour, or where new foundations sit within three or six metres of their wall, the Party Wall etc. Act applies and you serve notices as building owner. This is common on the tighter plots in CR7 and SE25. We coordinate the planning, a programme around your party wall notices, the groundworks and the internal fit-out so the whole build stays under one accountable team.

Kitchen extensions in Croydon

50% of the houses in Croydon 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 Croydon; the build figures are in the table above.

• Wrap-around extensions and infills
• Foundations, groundworks and steel frames
• Drawings and the structural engineer's design coordinated for you

VOA Council Tax stock of properties, March 2025, for all 45 statistical areas in Croydon. Counts rounded by the VOA.

Useful next reading for a house extensions project in Croydon: RSJ and steel beam installation in Croydon, our Croydon area guide, side return infills, the Party Wall Act process for extensions, house extensions across London and Double Storey Extension Cost.

Trusted House Extensions in Croydon

Croydon homeowners choose GS Renovation because we build the extension and finish it, rather than leaving a shell. From foundations and steels to plastering, kitchen and decoration, one team is accountable throughout. With our founder's 30+ years on the tools, we know the borough's housing, the plots and how Croydon Council handles planning and building control.

• Fully insured, with cover in place on every site
• Garden levels and access made good where the build meets outside
• Foundation depth set after trial holes, drains and trees are checked

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.