Wraparound extensions in Windsor
Our design and build teams take on wraparound extensions in Windsor, from the first measured survey through planning and building control to the finished room.
- Guide price in WindsorFrom £40,000 inc VAT
- PlanningUsually a householder application
- Build time14–20 weeks on site
- Postcode districtsSL1, SL3, SL4
Working in Windsor
Our survey diary covers Windsor, including SL1, SL3, SL4. Nearby, we also take on projects in Slough (2 miles), Maidenhead (6 miles), Bracknell (8 miles), Wokingham (11 miles).
Just over the Surrey border, Egham is about 4 miles away. 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 wraparound extension right for your house?
- Terraced houses that want the largest ground floor possible
- Semi-detached houses with a side passage
- Families who want kitchen, dining and living in one space
Do I need planning permission in Windsor?
In England a wraparound extension is assessed as both a side and a rear extension, and the combination usually falls outside permitted development, so most need a householder planning application (£548 from 1 April 2026).
The planning position for a specific Windsor 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.
Applications are decided by the local planning authority (your district, borough or unitary council).
How much does a wraparound extension cost in Windsor?
These guide figures apply our South East England adjustment (×1.12) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Windsor: £2,240 to £4,140 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Compact L-shape 18 m² | £40,000 – £48,500 | £46,000 – £58,500 | £58,000 – £75,000 |
| Medium L-shape 25 m² | £56,000 – £67,500 | £64,000 – £81,500 | £81,000 – £104,000 |
| Large L-shape 32 m² | £71,500 – £86,500 | £82,000 – £104,000 | £103,500 – £133,000 |
Want a range for your exact size? The guide-price tool takes about a minute.
What happens next
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
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Questions people ask about wraparound extensions
How long does a wraparound extension take to build in Windsor?
On site, typically 14 to 20 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Will my neighbours in Windsor be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of Windsor?
Yes. We cover Windsor and the surrounding parts of Berkshire. Site visits are free and there is no obligation.
Is a wraparound better than a side return alone?
It adds far more space, but costs more and needs planning permission more often. Our comparison guide sets the two side by side.
Do wraparound extensions need planning permission?
Usually, yes. In England the side element counts as a side extension and the rear element as a rear extension, and the combination normally falls outside permitted development. A householder application costs £548 in England from 1 April 2026.
Book a free site visit in Windsor
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.