Windsor, Berkshire
Two-storey rear extension in Windsor
We plan and build two-storey rear extensions for homeowners in Windsor. A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. Start with a free site visit, then a written price once the design is agreed.
Windsor and its postcode districts SL4 are part of our Berkshire coverage. In Berkshire we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning.
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 two-storey rear extension cost in Windsor?
For Windsor we work from the South East England rate: £2,020–£3,020 per square metre of new floor, including VAT, 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 × 5 m footprint, two floors (30 m²) | £60,500–£90,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £97,000–£145,000 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission for a two-storey rear extension in Windsor?
Whether your two-storey rear extension in Windsor needs a planning application depends on its size, your house and any local restrictions.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
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 Windsor like to extend?
Windsor 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 two-storey rear extension in Windsor comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
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.
Two-storey rear extensions near Windsor
Neighbouring places we cover include Slough (1.8 miles) and Egham (4.1 miles).
- Two-storey rear extension in Slough
- Two-storey rear extension in Egham
- Two-storey rear extension in Burnham
- Two-storey rear extension in Staines
- Two-storey rear extension in Stanwell
Other work in Windsor:
FAQ
Two-storey rear extension questions in Windsor
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 you handle building control in Windsor?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Is two-storey cheaper per square metre than single-storey?
Usually yes, because the foundations and roof are shared across twice the floor area. The total cost is higher.
Is the site visit in Windsor free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
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 much does a two-storey rear extension cost in Windsor?
As a guide, £2,020–£3,020 per square metre including VAT for a standard specification. For example, 3 m × 5 m footprint, two floors (30 m²): about £60,500–£90,500 at that rate. Your written price follows the survey.