House Extensions Cockfosters

A Cockfosters back garden is long enough that a rear extension rarely feels like it is eating the plot, which is why it is the project we build most in EN4. GS Renovation runs the whole thing: foundations, steel, roof, glazing and fit-out, with Barnet Council planning or a lawful development certificate handled alongside.

Rear extensions on the long gardens of Cockfosters

Depth is the advantage here. Where a house on a tighter plot has to settle for a side return, a Cockfosters house can usually take a proper rear extension and still keep a garden worth sitting in. Foundations come first, and they are dictated by the ground and by what is growing in it; the mature trees around Trent Park and along the older roads mean a deeper foundation or a reinforced design is sometimes needed rather than the standard trench fill everyone assumes will do.

Tying new work into a 1930s cavity wall takes some care. The existing rear wall is opened up on a beam, the cavity is trayed and closed at the junction, and the new roof is properly flashed into the original brickwork rather than sealed with mastic and optimism. We match brick and bond as closely as the original allows, knowing that ninety year old stock has weathered and a modern facing will always read slightly newer until it has dulled down over a few London winters.

Permitted development and Barnet Council in EN4

Many single storey rear extensions in Cockfosters are permitted development. A semi-detached house is allowed three metres of depth and a detached house four, with a maximum height of four metres, eaves no higher than three metres within two metres of a boundary, and no more than half the original garden built over. The larger home extension procedure can double those depths, subject to prior approval and a neighbour consultation period. Rights are removed in Article 4 areas, so the address is checked before design starts.

We recommend applying for a lawful development certificate even where a scheme clearly sits within permitted development, because it is the evidence a buyer's conveyancer will want and it is far less trouble to obtain now than later. Building regulations approval is separate and always required, covering structure, insulation, drainage and fire safety. Digging foundations within three metres of a neighbour's foundations and deeper than they sit is notifiable under the Party Wall etc. Act 1996, which is worth checking even on these wide plots.

• Brickwork and mortar matched to the existing elevation
• Party Wall Act notices for excavation near a neighbour's wall
• Single and double storey extensions
• Flat and pitched roofs with rooflights or lanterns
• Steel goalpost frames where the rear wall opens up

Work in Cockfosters rarely sits on its own, so you may also want Load-bearing wall removal in Cockfosters, House extensions across Barnet, wraparound extensions and side return vs rear extension.

The GS Renovation Difference in Cockfosters

GS Renovation builds extensions in Cockfosters as one job with one point of contact, from setting out the foundations to the last coat of paint. We tell you honestly whether a scheme is permitted development or needs an application to Barnet Council, coordinate the structural engineer, keep building control inspections on schedule and work tidily in a house you are still living in. Founder-led and fully insured.

• Weathertight shell reached before the fit-out begins
• Foundation depth set after trial holes, drains and trees are checked
• Scaffolding and site set-up planned for tight London plots
• A dedicated project manager from first survey to handover
• Rated 4.9 from 31 reviews on MyBuilder
• Free, no-obligation quotations

Written and reviewed by Abdelaaziz Saaid, founder of GS Renovation Ltd, who has spent more than 30 years on the tools and on site in London homes. Structural design is specified by the consulting engineer appointed to your project.