What is a single-storey extension?
A single-storey extension is a ground-floor addition, usually at the rear of a house, that enlarges a kitchen, living or dining space. Most are built with cavity walls on concrete foundations and finished with a flat roof and roof lantern or a pitched tiled roof.
How much does a single-storey extension cost in East Dereham?
In East Dereham, a single-storey extension typically costs £2,050–£3,050 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £41,000–£61,000. That range is adjusted for the East of England, where domestic building work typically costs around 6% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £28,500–£42,500 |
| Typical project (20 m²) | £41,000–£61,000 |
| Larger project (28 m²) | £57,500–£85,500 |
| Rate per m² | £2,050–£3,050 |
The biggest cost drivers are:
- Kitchen, flooring and finishes, which we can include or leave to you
- Floor area and the length of new wall
- How much of the existing house is opened up
- Ground conditions and foundation depth
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a single-storey extension in East Dereham?
Before anything is built in East Dereham, we confirm which approvals apply in England. In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most single-storey extensions:
- Foundations, drainage and any build-over agreement
- Building control inspections and completion certificate
- Knock-through to the existing house with steel beams
- Doors, windows and roof glazing installed
- Structural calculations for steels and lintels
- Measured survey and design drawings
How long does it take?
Build time is typically 10 to 14 weeks on site for a typical rear extension, after approvals. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in East Dereham
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
Our East Dereham coverage includes postcode districts NR19, and we also work in nearby places such as Bowthorpe, Norwich and Thetford.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about single-storey extensions in East Dereham
How much does a single-storey extension cost in East Dereham?
In East Dereham, a single-storey extension typically costs £2,050–£3,050 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £41,000–£61,000. Your fixed price depends on the survey and drawings.
How long does a single-storey extension take?
Once approvals are in place, a typical rear extension takes 10 to 14 weeks on site. Design and approvals usually take another 6 to 12 weeks beforehand, depending on whether a planning application is needed.
Is VAT charged on an extension?
Yes. Building work on an existing home is standard-rated, so VAT at 20% applies. Our guide prices include it.
Who approves a single-storey extension in East Dereham?
Planning matters in East Dereham go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
What is a build-over agreement?
If a public sewer runs within 3 metres of the extension, the water company normally has to agree to the work before it starts. We check sewer records during design and apply where needed.