Northumberland
Single-storey rear extensions in Northumberland
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We design and build rear extensions across Northumberland, from Blyth and Cramlington to Ashington, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.
On terraces and semis like those around Blyth, a single-storey rear extension is usually the simplest way to fix a small back kitchen without touching the bedrooms. Terraces and semis are typical around Northumberland. On terraces a single-storey rear extension across the back yard is usually the practical choice; semis often have room for more.
How much does a single-storey rear extension cost in Northumberland?
Guide prices for a single-storey rear extension in Northumberland start from our North East England rate of £1,710–£2,790 per square metre, including VAT. North East prices are among the lowest in our range; former mining ground is the main foundation variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £20,500–£33,500 |
| 4 m wide × 5 m deep (20 m²) | £34,000–£56,000 |
| 4 m wide × 6 m deep (24 m²) | £41,000–£67,000 |
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 in Northumberland?
In England a single-storey rear extension can often be built under permitted development: up to 3 metres beyond the original rear wall of an attached house, or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres if any part is 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.
Where in Northumberland do we work?
FAQ
Questions people ask
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.
Is a flat roof or a pitched roof better?
A warm flat roof keeps the extension low under first-floor windows and suits a roof lantern; a pitched or lean-to roof gives a vaulted ceiling. Both last for decades when built properly.
Can I stay in the house during the build?
Usually yes. The noisiest, dustiest stage, removing the back wall, is kept to the final weeks and screened off. Most families set up a temporary kitchen elsewhere in the house.
Do you cover all of Northumberland?
We cover 10 towns and districts in Northumberland, including Blyth, Cramlington and Ashington.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.