Windsor, Berkshire
Side return extension in Windsor
We plan and build side return extensions for homeowners in Windsor. Infilling the narrow passage beside a Victorian or Edwardian back addition. Start with a free site visit, then a written price once the design is agreed.
Windsor sits in Berkshire, with postcode districts including SL4. In Windsor we check the boundary line and the neighbour's gutter before drawing a side return, because a few centimetres decide whether the wall goes on or beside the boundary.
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 side return extension cost in Windsor?
Guide prices for a side return extension in Windsor start from our South East England rate of £2,580–£4,260 per square metre, including VAT. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 2 m wide × 6 m deep (12 m²) | £31,000–£51,000 |
| 2.5 m wide × 7 m deep (17.5 m²) | £45,000–£74,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission for a side return extension in Windsor?
The planning route for a side return extension in Windsor is set by England's householder rules and your council.
In England the side part of a side return or wraparound must meet the side-extension rules (one storey, under 4 metres high, no more than half the width of the original house), and those rights do not apply on designated land. Because a wraparound combines a side and a rear extension, many need householder planning permission.
Because rear extensions often sit on or near the boundary, the Party Wall etc. Act 1996 usually applies in England. Notices go out one or two months before work depending on the type of work, and a surveyor's award is only needed if a neighbour does not consent.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
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 side return extension in Windsor comes together
Free site visit
We measure the house and garden, look at the back wall, drainage and boundaries, and talk through what you want from the space.
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.
Side return extensions near Windsor
We also build side return extensions in nearby Slough (1.8 miles) and Egham (4.1 miles).
- Side return extension in Slough
- Side return extension in Egham
- Side return extension in Burnham
- Side return extension in Staines
- Side return extension in Stanwell
Other work in Windsor:
FAQ
Side return extension questions in Windsor
Do I need planning permission for a rear extension in Windsor?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.
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.
Glass roof or solid roof with rooflights?
A glass roof gives the most light; a solid roof with long rooflights is warmer and quieter in rain. Both work.
How much does a side return extension cost in Windsor?
As a guide, £2,580–£4,260 per square metre including VAT for a standard specification. For example, 2 m wide × 6 m deep (12 m²): about £31,000–£51,000 at that rate. Your written price follows the survey.
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.