Sunbury-on-Thames, Surrey
Single-storey rear extension in Sunbury-on-Thames
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. If you live in Sunbury-on-Thames 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.
Sunbury-on-Thames is covered from our Surrey round, including KT12, TW16 and TW17. A depth of 3 to 4 metres keeps many single-storey rear extensions in Sunbury-on-Thames within permitted development, subject to the house's planning history.
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 Sunbury-on-Thames?
In Sunbury-on-Thames, 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 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a single-storey rear extension in Sunbury-on-Thames?
The planning route for a single-storey rear extension in Sunbury-on-Thames is set by England's householder rules and your council.
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. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Sunbury-on-Thames like to extend?
Sunbury-on-Thames has a mix of Victorian terraces near the centre and larger Edwardian and inter-war houses further out. Clay soils across much of the South East mean deeper foundations near trees, which we plan for at the survey.
How a single-storey rear extension in Sunbury-on-Thames 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.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
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 Sunbury-on-Thames
From Sunbury-on-Thames, the nearest places we also cover are Walton-on-Thames (1.2 miles) and Shepperton (1.5 miles).
- Single-storey rear extension in Walton-on-Thames
- Single-storey rear extension in Shepperton
- Single-storey rear extension in West Molesey
- Single-storey rear extension in Hampton
- Single-storey rear extension in Hanworth
Other work in Sunbury-on-Thames:
FAQ
Single-storey rear extension questions in Sunbury-on-Thames
Is the site visit in Sunbury-on-Thames free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
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.
How deep can a single-storey rear extension be without planning?
In England, 3 metres on an attached house and 4 metres on a detached house under permitted development, or up to 6 and 8 metres with prior approval. Wales allows 4 metres; Scotland and Northern Ireland have their own limits.
Do you handle building control in Sunbury-on-Thames?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
How long does a rear extension take to build in Sunbury-on-Thames?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.