High Wycombe side extensions, designed and built
High Wycombe 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 High WycombeFrom £24,500 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsHP10, HP11, HP12, HP13, HP14
When a side extension makes sense
- Detached and semi-detached houses with side land
- Homes needing a utility, study or ground-floor bedroom
- Houses where the rear garden is small
Side extension prices in High Wycombe
Labour and material costs vary across the UK, so for High Wycombe we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in High Wycombe: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
Working in High Wycombe
We cover High Wycombe and the postcode districts HP10, HP11, HP12, HP13, HP14, HP15. We also work in nearby Marlow (4 miles), Amersham (6 miles), Chesham (8 miles), Chalfont St Peter (8 miles).
Maidenhead, in Berkshire, is roughly 7 miles from High Wycombe and also on our list. 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.
Planning and approvals in High Wycombe
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.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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.
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).
From first visit to completion
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 High Wycombe home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in High Wycombe
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for High Wycombe, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Do you cover all of High Wycombe?
Yes. We cover High Wycombe and the surrounding parts of Buckinghamshire. Site visits are free and there is no obligation.
Who do I contract with for a side extension in High Wycombe?
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.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
How much does a side extension cost?
Our guide range is about £1,960 to £3,810 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £41,000 to £53,500 in High Wycombe.
Book a free site visit in High Wycombe
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.