Northamptonshire
Rear extensions for terraced houses in Northamptonshire
Rear and side return extensions for terraces, with access through the house and two neighbours. Across Northamptonshire we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Northampton, Corby and Kettering.

On a Northampton terrace both neighbours usually need party wall notices or agreement, so we talk to them early. Northamptonshire has plenty of inter-war semis and bungalows, and single-storey rear extensions suit both.
How much does a terraced house rear extension cost in Northamptonshire?
In Northamptonshire, our guide for a terraced house rear extension is £1,990–£3,200 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 × 4.5 m deep (13.5 m²) | £27,000–£43,000 |
| 3 m wide × 6 m deep (18 m²) | £36,000–£57,500 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission in Northamptonshire?
Under England's householder permitted development rules you can usually add 3 metres at the back of an attached house, or 4 metres on a detached house, without a planning application, as long as the extension stays under 4 metres high and its eaves stay under 3 metres where it is within 2 metres of a boundary.
The Party Wall etc. Act 1996 applies in England: you serve notice two months before work to a shared wall, and one month before digging foundations within 3 metres (or 6 metres for deeper foundations) of a neighbour's building. Neighbours can agree in writing; if they dissent, surveyors agree an award.
Conservation areas, National Parks, National Landscapes and the Broads restrict permitted development, and listed buildings always need listed building consent.
Where in Northamptonshire do we work?
FAQ
Questions people ask
Can you build without side access?
Yes. Materials come through the house in protected runs or over the roof by crane on tight sites.
Do both neighbours need party wall notices?
Usually yes in England and Wales, because the extension often sits on or near both boundaries.
How deep can I go on a terrace?
3 metres under permitted development in England, or up to 6 metres with prior approval outside designated land.
Do you cover all of Northamptonshire?
We cover 8 towns and districts in Northamptonshire, including Northampton, Corby and Kettering.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.