Cumbria
Glazed and glass-box rear extensions in Cumbria
Full-height glass, slim frames and big rooflights for the most open rear room. Across Cumbria we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Carlisle, Barrow in Furness and Kendal.
If your garden in Carlisle faces south, expect us to talk about overhangs and solar-control glass before frame colours. 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 glazed rear extension cost in Cumbria?
A glazed rear extension in Cumbria is priced at £2,630–£4,510 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) | £31,500–£54,000 |
| 4 m wide × 6 m deep (24 m²) | £63,000–£108,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission in Cumbria?
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.
New fabric must meet Approved Document L (2021 edition incorporating 2023 amendments): walls 0.18, roof 0.15 and floor 0.18 W/m²K, windows 1.4 W/m²K or Band B. Under the simple route, new windows, doors and rooflights should not exceed 25% of the extension floor area plus any openings removed; more glass is possible with a whole-house calculation.
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
Will a glass extension be too hot?
Not if it is designed for its orientation, with solar-control glass, shading and ventilation.
Is there a limit on how much glass I can have?
In England the simple rule is 25% of the floor area plus openings removed; more is allowed with a calculation showing the house still meets Part L.
Sliding or bifold doors?
Sliders give bigger panes and slimmer sightlines; bifolds open the whole width. Our guide compares them.
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.