Cumbria
Single-storey rear extensions in Cumbria
Ground-floor space across the back of the house, usually for a kitchen, dining or family room. We design and build rear extensions across Cumbria, from Carlisle and Barrow in Furness to Kendal, covering single-storey kitchen extensions, two-storey additions, side returns and wraparounds.

On stone and brick terraces like those around Carlisle, a single-storey rear extension is usually the simplest way to fix a small back kitchen without touching the bedrooms. Stone and brick terraces are common around Cumbria. Where houses back onto a ginnel or alley, deliveries can come in from the rear, which makes the build tidier.
How much does a single-storey rear extension cost in Cumbria?
A single-storey rear extension in Cumbria is priced at £1,790–£2,910 per square metre including VAT as a guide, before kitchen fit-out and fees. North West prices sit below our West Midlands baseline; access on terraced streets is the main variable.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £21,500–£35,000 |
| 4 m wide × 5 m deep (20 m²) | £35,500–£58,500 |
| 4 m wide × 6 m deep (24 m²) | £43,000–£70,000 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission in Cumbria?
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 Cumbria 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 Cumbria?
We cover 7 towns and districts in Cumbria, including Carlisle, Barrow in Furness and Kendal.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.