Northampton, Northamptonshire
Two-storey rear extension in Northampton
For homes in Northampton, a two-storey rear extension is often the simplest way to gain space without moving. A larger kitchen downstairs and an extra bedroom or bathroom upstairs, under one roof. We take it from survey to completion certificate.
Northampton sits in Northamptonshire, with postcode districts including NN1, NN2, NN3 and NN4. In Northamptonshire we check the neighbours' rear windows first, because the upper floor is where most two-storey schemes win or lose planning.
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 two-storey rear extension cost in Northampton?
Guide prices for a two-storey rear extension in Northampton start from our East Midlands rate of £1,750–£2,620 per square metre, including VAT. East Midlands prices sit a little below our West Midlands baseline.
| Size | Guide price inc VAT |
|---|---|
| 3 m × 5 m footprint, two floors (30 m²) | £52,500–£78,500 |
| 4 m × 6 m footprint, two floors (48 m²) | £84,000–£125,500 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a two-storey rear extension in Northampton?
Here is how the rules in England apply to a two-storey rear extension in Northampton.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent. At the first visit we measure what is there now and tell you which route fits: permitted development, prior approval or a planning application.
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 two-storey rear extension in Northampton 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.
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.
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.
Two-storey rear extensions near Northampton
Close by, we work in Wellingborough, about 8.8 miles away, and Daventry, about 11.7 miles away.
- Two-storey rear extension in Wellingborough
- Two-storey rear extension in Daventry
- Two-storey rear extension in Rushden
- Two-storey rear extension in Kettering
- Two-storey rear extension in Newport Pagnell
Other work in Northampton:
FAQ
Two-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 I need planning permission for a rear extension in Northampton?
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.
What is the 45-degree rule?
Many councils check that a two-storey extension does not cross a 45-degree line drawn from the nearest habitable window of the neighbouring house. We test it at the first drawing.
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.
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 long does a rear extension take to build in Northampton?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.