Daventry, Northamptonshire
Semi-detached rear extension in Daventry
Single or two-storey extensions for semi-detached houses, with side access and one party wall. We design, get the approvals for and build rear extensions for semi-detached houses in Daventry and the surrounding area, with one contract from the first survey to building control sign-off.
Daventry sits in Northamptonshire, with postcode districts including NN11. In Daventry we measure the attached neighbour's extension at the survey, because it often sets the sensible depth for yours.
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 semi-detached rear extension cost in Daventry?
In Daventry, our guide for a semi-detached rear extension is £1,840–£3,010 per square metre including VAT for a standard specification. 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 |
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 semi-detached rear extension in Daventry?
Here is how the rules in England apply to a semi-detached rear extension in Daventry.
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.
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.
England also has the larger home extension route: a single-storey rear extension of up to 6 metres on an attached house or 8 metres on a detached house, after prior approval from the council. The council notifies your neighbours and has 42 days to decide; the fee is £249 (£310 for applications made from 8 December 2026). The route is not available on designated land such as conservation areas.
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 Daventry like to extend?
Daventry has plenty of inter-war semis and bungalows, and single-storey rear extensions suit both.
How a semi-detached rear extension in Daventry 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.
Drawings and budget
Floor plans and elevations for the options, each with a guide price.
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.
Semi-detached rear extensions near Daventry
Neighbouring places we cover include Rugby (9.0 miles) and Northampton (11.7 miles).
- Semi-detached rear extension in Rugby
- Semi-detached rear extension in Northampton
- Semi-detached rear extension in Royal Leamington Spa
- Semi-detached rear extension in Banbury
- Semi-detached rear extension in Brackley
Other work in Daventry:
FAQ
Semi-detached rear extension questions in Daventry
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 you handle building control in Daventry?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
What if my neighbour has already extended?
That can make a matching depth easier to justify. We measure theirs at the survey.
Is the site visit in Daventry free?
Yes. We visit, measure up and talk through the options with no cost and no obligation.
Can you match the brick or stone on my Daventry house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
Do I need planning permission for a rear extension in Daventry?
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.