Side extensions in Slough
Slough homeowners can use us for the whole side extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in SloughFrom £24,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsSL1, SL2, SL3, SL4
Guide prices for Slough
Prices below are for Slough, 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 Slough: £1,960 to £3,810 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £24,500 – £30,000 | £27,500 – £36,000 | £34,500 – £46,000 |
| 3 m × 6 m 18 m² | £35,000 – £42,500 | £41,000 – £53,500 | £52,000 – £69,000 |
| 3 m × 8 m 24 m² | £47,000 – £56,500 | £55,000 – £71,500 | £69,500 – £91,500 |
Try the guide-price tool to see a range for your own size and finish.
Working in Slough
We cover Slough and the postcode districts SL1, SL2, SL3, SL4. The same team covers Windsor (2 miles), Maidenhead (5 miles), Bracknell (9 miles), Wokingham (12 miles), all within easy reach.
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.
Do I need planning permission in Slough?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
The planning position for a specific Slough 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).
What is included
- Windows, doors and finishes to match
- Structure, roof tied into the house
- Survey, design and street-view drawings
- New openings through the side wall
- Foundations near boundaries and any drains
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
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
We visit your Slough home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Slough
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Slough, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Who do I contract with for a side extension in Slough?
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.
How long does a side extension take to build in Slough?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a planning application.
How close to the boundary can I build?
It depends on height. In England, within 2 m of a boundary the eaves must not exceed 3 m under permitted development. Building on the boundary is possible but brings party wall and maintenance access issues we plan for.
Book a free site visit in Slough
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.