Side return extensions for homes in Chalfont St Peter
Our design and build teams take on side return extensions in Chalfont St Peter, from the first measured survey through planning and building control to the finished room.
- Guide price in Chalfont St PeterFrom £20,000 inc VAT
- PlanningOften permitted development; party wall notice usual
- Build time10–14 weeks on site
- Postcode districtsSL9
How much does a side return extension cost in Chalfont St Peter?
Labour and material costs vary across the UK, so for Chalfont St Peter we use our South East England factor (×1.12). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Chalfont St Peter: £2,350 to £4,260 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £20,000 – £24,000 | £21,500 – £27,000 | £26,500 – £34,500 |
| 2 m × 5.5 m 11 m² | £25,500 – £31,000 | £29,500 – £37,000 | £36,500 – £47,000 |
| 2.2 m × 7 m 15 m² | £35,000 – £42,500 | £40,000 – £50,500 | £50,000 – £64,000 |
Try the guide-price tool to see a range for your own size and finish.
What is included
- Survey of the outrigger, boundary wall and drainage
- Design to keep daylight in the middle of the house
- New boundary wall or raised party wall
- Kitchen-ready shell or full finish
Extensions in and around Chalfont St Peter
Site visits are available across Chalfont St Peter (SL9). We also work in nearby Gerrards Cross (2 miles), Amersham (5 miles), Chesham (7 miles), High Wycombe (8 miles).
Rickmansworth, in Hertfordshire, is roughly 4 miles from Chalfont St Peter and also on our list. In the South East, plenty of houses have already been extended once, which makes checking the remaining permitted development allowance an important early step.
Do I need planning permission in Chalfont St Peter?
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
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).
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
We visit your Chalfont St Peter 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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Side return extension questions answered
Do I need building regulations approval in Chalfont St Peter?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Chalfont St Peter 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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Chalfont St Peter, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Can I combine a side return with a rear extension?
Yes. That combination is a wraparound extension, which adds the most space to a terraced house.
How much does a side return extension cost?
Our guide range is about £2,350 to £4,260 per m² including VAT, so a typical 2 m × 5.5 m infill lands around £29,500 to £37,000 at standard spec in Chalfont St Peter, more in London.
Book a free site visit in Chalfont St Peter
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.