Desborough, Northamptonshire
Semi-detached rear extension in Desborough
Single or two-storey extensions for semi-detached houses, with side access and one party wall. If you live in Desborough and want to know what a semi-detached rear extension would cost and whether it needs planning, start with the online guide price or a free site visit.
Desborough is covered from our Northamptonshire round, including LE16. In Desborough 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 Desborough?
For Desborough we work from the East Midlands rate: £1,840–£3,010 per square metre of new floor, including VAT, 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 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission for a semi-detached rear extension in Desborough?
Here is how the rules in England apply to a semi-detached rear extension in Desborough.
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.
A two-storey rear extension can be permitted development in England only if it projects no more than 3 metres, stays at least 7 metres from the rear boundary, matches the existing roof pitch and has obscure-glazed upper side windows. In practice most double-storey rear extensions go through a householder planning application.
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 Desborough like to extend?
Desborough has plenty of inter-war semis and bungalows, and single-storey rear extensions suit both.
How a semi-detached rear extension in Desborough 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.
Paperwork handled
Planning, prior approval or permitted development, Building Regulations approval, structural design and party wall notices are all handled by us.
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.
Semi-detached rear extensions near Desborough
Close by, we work in Market Harborough, about 4.9 miles away, and Kettering, about 5.0 miles away.
- Semi-detached rear extension in Market Harborough
- Semi-detached rear extension in Kettering
- Semi-detached rear extension in Corby
- Semi-detached rear extension in Wellingborough
- Semi-detached rear extension in Northampton
Other work in Desborough:
FAQ
Semi-detached rear extension questions in Desborough
Can you match the brick or stone on my Desborough house?
We source the closest match and show you samples before ordering; reclaimed materials are often the best match on older houses.
What postcode areas do you cover around Desborough?
Including LE16, and the surrounding Northamptonshire area.
Do I need a party wall agreement?
Usually with the attached neighbour, in England and Wales.
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.
Do I need planning permission for a rear extension in Desborough?
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.
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.