Side return extensions for homes in Sunbury-on-Thames
Planning a side return extension in Sunbury-on-Thames? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in Sunbury-on-ThamesFrom £20,000 inc VAT
- PlanningOften permitted development; party wall notice usual
- Build time10–14 weeks on site
- Postcode districtsKT12, TW16, TW17
Planning rules that apply in Sunbury-on-Thames
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
The planning position for a specific Sunbury-on-Thames address depends on its history and any designations, which is why we check it at the first visit.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
Guide prices for Sunbury-on-Thames
Labour and material costs vary across the UK, so for Sunbury-on-Thames we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Sunbury-on-Thames: £2,350 to £4,260 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £20,000 – £24,000 | £21,500 – £27,000 | £26,500 – £34,500 |
| 2 m × 5.5 m 11 m² | £25,500 – £31,000 | £29,500 – £37,000 | £36,500 – £47,000 |
| 2.2 m × 7 m 15 m² | £35,000 – £42,500 | £40,000 – £50,500 | £50,000 – £64,000 |
Try the guide-price tool to see a range for your own size and finish.
Extensions in and around Sunbury-on-Thames
Across KT12, TW16, TW17, we can visit, measure and advise. Nearby, we also take on projects in Walton-on-Thames (1 mile), West Molesey (2 miles), Ashford, Surrey (3 miles), Weybridge (3 miles).
Homes across the South East range from Victorian terraces in the older town centres to large detached houses on the edges, so the right extension type varies street by street.
Is a side return extension right for your house?
- Victorian and Edwardian terraces with a rear outrigger
- Homes where the garden is too small to lose much depth
- Narrow galley kitchens
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Sunbury-on-Thames
How long does a side return extension take to build in Sunbury-on-Thames?
On site, typically 10 to 14 weeks once approvals are in place. Before that, allow 6–12 weeks design and approvals.
Who do I contract with for a side return extension in Sunbury-on-Thames?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Sunbury-on-Thames?
Yes. We cover Sunbury-on-Thames and the surrounding parts of Surrey. Site visits are free and there is no obligation.
Can I combine a side return with a rear extension?
Yes. That combination is a wraparound extension, which adds the most space to a terraced house.
Will the kitchen be darker?
Not if the roof is designed well. A glazed roof or a line of rooflights along the boundary usually makes the room brighter than before.
Book a free site visit in Sunbury-on-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.