Single-storey rear extensions for homes in Staines-upon-Thames
From the first sketch to final sign-off, we plan and build single-storey extensions in Staines-upon-Thames and the surrounding Surrey area.
- Guide price in Staines-upon-ThamesFrom £23,500 inc VAT
- PlanningOften permitted development (3–4 m), or prior approval up to 6–8 m
- Build time10–16 weeks on site
- Postcode districtsTW15, TW18, TW19, TW20

Extensions in and around Staines-upon-Thames
We cover Staines-upon-Thames and the postcode districts TW15, TW18, TW19, TW20. Nearby, we also take on projects in Egham (2 miles), Ashford, Surrey (2 miles), Sunbury-on-Thames (4 miles), Weybridge (5 miles).
Feltham, in Greater London, is roughly 4 miles from Staines-upon-Thames and also on our list. The South East has a broad mix of 1930s semis, post-war estates, newer developments and period cottages, and many houses have enough garden for a generous rear extension.
Included in a typical project
- Building regulations drawings and structural calculations
- Planning route checked and the right approval obtained
- Measured survey and design
- Walls, steel beams and the new opening into the house
- Foundations, drainage and groundworks
Depth is the big decision. Every extra metre adds floor area but also takes garden and can push you out of permitted development. We draw the room at two or three depths so you can see the trade-off in space, light and cost before anything is fixed.
Planning rules that apply in Staines-upon-Thames
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does a single-storey extension cost in Staines-upon-Thames?
Prices below are for Staines-upon-Thames, using the South East England factor of ×1.12. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Staines-upon-Thames: £1,960 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £23,500 – £28,000 | £27,500 – £35,000 | £34,500 – £46,000 |
| 4 m × 5 m 20 m² | £39,000 – £46,000 | £45,500 – £58,500 | £58,000 – £76,500 |
| 5 m × 6 m 30 m² | £58,500 – £69,000 | £68,500 – £87,500 | £87,000 – £114,500 |
Try the guide-price tool to see a range for your own size and finish.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Single-storey extension questions answered
Do I need building regulations approval in Staines-upon-Thames?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Staines-upon-Thames, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a single-storey extension take to build in Staines-upon-Thames?
On site, typically 10 to 16 weeks once approvals are in place. Before that, allow 4–12 weeks design and approvals.
Will I need a steel beam?
Almost always. Opening up the rear wall to join the new room to the house needs a beam, usually steel, sized by a structural engineer. It is included in our quotes.
How much does a single-storey extension cost per square metre?
Our guide range is about £1,960 to £3,810 per m² including VAT, depending on specification. A standard-spec 4 m × 5 m room usually lands at £45,500 to £58,500 in Staines-upon-Thames, plus design and council fees.
Book a free site visit in Staines-upon-Thames
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.