Cobham, Surrey
Single-storey rear extension in Cobham
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. If you live in Cobham and want to know what a single-storey rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Cobham is covered from our Surrey round, including KT11. On inter-war semis and 1960s estates like those around Cobham, a single-storey rear extension is usually the simplest way to fix a small back kitchen without touching the bedrooms.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a single-storey rear extension cost in Cobham?
In Cobham, our guide for a single-storey rear extension is £2,130–£3,470 per square metre including VAT for a standard specification. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £25,500–£41,500 |
| 4 m wide × 5 m deep (20 m²) | £42,500–£69,500 |
| 4 m wide × 6 m deep (24 m²) | £51,000–£83,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a single-storey rear extension in Cobham?
Here is how the rules in England apply to a single-storey rear extension in Cobham.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres within 2 metres of a boundary.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Cobham like to extend?
Around Cobham the housing ranges from inter-war semis to 1960s and 1970s estates with good-sized gardens. Many of the newer estates had permitted development rights removed by condition, so we check the planning history before anything is drawn.
How a single-storey rear extension in Cobham comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Build and sign-off
We build to the approved drawings with regular updates, then hand over the building control completion certificate and any guarantees from suppliers.
Single-storey rear extensions near Cobham
From Cobham, the nearest places we also cover are Esher (3.3 miles) and Weybridge (3.6 miles).
- Single-storey rear extension in Esher
- Single-storey rear extension in Weybridge
- Single-storey rear extension in Great Bookham
- Single-storey rear extension in Walton-on-Thames
- Single-storey rear extension in Leatherhead
Other work in Cobham:
FAQ
Single-storey rear extension questions in Cobham
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
Will the extension make the room behind it dark?
Not if it is designed well. Rooflights or a lantern over the old back room, and a wide opening into it, keep daylight reaching the middle of the house.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Can you match the brick or stone on my Cobham house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
What postcode areas do you cover around Cobham?
Including KT11, and the surrounding Surrey area.