Northampton, Northamptonshire
Single-storey rear extension in Northampton
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We design, get the approvals for and build single-storey rear extensions in Northampton and the surrounding area, with one contract from the first survey to building control sign-off.
Northampton sits in Northamptonshire, with postcode districts including NN1, NN2, NN3 and NN4. A depth of 3 to 4 metres keeps many single-storey rear extensions in Northampton within permitted development, subject to the house's planning history.
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 Northampton?
Guide prices for a single-storey rear extension in Northampton start from our East Midlands rate of £1,840–£3,010 per square metre, including VAT. East Midlands prices sit a little below our West Midlands baseline.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £22,000–£36,000 |
| 4 m wide × 5 m deep (20 m²) | £37,000–£60,000 |
| 4 m wide × 6 m deep (24 m²) | £44,000–£72,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a single-storey rear extension in Northampton?
Here is how the rules in England apply to a single-storey rear extension in Northampton.
English permitted development (Class A) allows a single-storey rear extension of 3 metres on a terraced or semi-detached house and 4 metres on a detached one, measured from the original house, with a maximum height of 4 metres and eaves of no more than 3 metres 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. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Northampton like to extend?
Red-brick terraces and semis are typical of Northampton. Coal-mining legacy areas in parts of the East Midlands can need a Coal Authority check before foundations are designed.
How a single-storey rear extension in Northampton comes together
Look round and measure
A free visit to see the back of the house, measure it, check the drains and boundaries and hear what you need.
Options and costs
We draw layout options and price each one, so the budget shapes the design rather than surprising you later.
Approvals
Permitted development check, prior approval or planning application, then Building Regulations drawings and structural calculations, plus party wall notices where they apply.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Single-storey rear extensions near Northampton
Neighbouring places we cover include Wellingborough (8.8 miles) and Daventry (11.7 miles).
- Single-storey rear extension in Wellingborough
- Single-storey rear extension in Daventry
- Single-storey rear extension in Rushden
- Single-storey rear extension in Kettering
- Single-storey rear extension in Newport Pagnell
Other work in Northampton:
FAQ
Single-storey rear extension questions in Northampton
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
Do you handle building control in Northampton?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
How deep can a single-storey rear extension be without planning?
In England, 3 metres on an attached house and 4 metres on a detached house under permitted development, or up to 6 and 8 metres with prior approval. Wales allows 4 metres; Scotland and Northern Ireland have their own limits.
Can I get a price without a visit?
Our online guide-price tool gives a range in a couple of minutes. A written price needs a survey.
Who will build my extension?
Vetted building teams working under contract to us. Your contract is with S&K Property Investments and Improvement Ltd for the design and the build.
Can you match the brick or stone on my Northampton house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.