Amersham, Buckinghamshire
Single-storey rear extension in Amersham
Single-storey rear extension in Amersham: ground-floor space across the back of the house, usually for a kitchen, dining or family room. We measure the house, show you what the rules allow, price it in writing and build it.
We cover Amersham (HP6 and HP7) as part of our Buckinghamshire work. A single-storey rear extension in Amersham is mostly built from the garden side, so the house stays usable for most of the job.
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 single-storey rear extension cost in Amersham?
A single-storey rear extension in Amersham is priced at £2,130–£3,470 per square metre including VAT as a guide, before kitchen fit-out and fees. South East prices run above our West Midlands baseline, mainly on labour rates and clay-soil foundations.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £25,500–£41,500 |
| 4 m wide × 5 m deep (20 m²) | £42,500–£69,500 |
| 4 m wide × 6 m deep (24 m²) | £51,000–£83,500 |
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 single-storey rear extension in Amersham?
Whether your single-storey rear extension in Amersham needs a planning application depends on its size, your house and any local restrictions.
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is within 2 metres of a boundary.
If 3 or 4 metres is not enough, England's prior approval route allows 6 metres on a terraced or semi-detached house and 8 metres on a detached house for a single-storey rear extension. Neighbours are consulted, the council decides within 42 days, and the fee is £249, rising to £310 from 8 December 2026.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. Before any drawing we look up the property's history with the council, because earlier extensions and removed rights change the answer.
What are homes in Amersham like to extend?
Commuter semis and detached houses make up much of Amersham, and longer gardens make England's prior approval route for deeper rear extensions worth considering.
How a single-storey rear extension in Amersham comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Single-storey rear extensions near Amersham
We also build single-storey rear extensions in nearby Amersham on the Hill (0.7 miles) and Chesham (2.4 miles).
- Single-storey rear extension in Amersham on the Hill
- Single-storey rear extension in Chesham
- Single-storey rear extension in Beaconsfield
- Single-storey rear extension in Chorleywood
- Single-storey rear extension in Chalfont St Peter
Other work in Amersham:
FAQ
Single-storey rear extension questions in Amersham
Do I need a party wall agreement?
In England, usually yes if the extension is on or near a shared boundary or the foundations are close to a neighbour's building. We serve the notices.
How much does a single-storey rear extension cost in Amersham?
As a guide, £2,130–£3,470 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £25,500–£41,500 at that rate. Your written price follows the survey.
Is a flat roof or a pitched roof better?
A warm flat roof keeps the extension low under first-floor windows and suits a roof lantern; a pitched or lean-to roof gives a vaulted ceiling. Both last for decades when built properly.
Do you handle building control in Amersham?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Do I need planning permission for a rear extension in Amersham?
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.
Is the site visit in Amersham free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.