County Durham
Glazed and glass-box rear extensions in County Durham
Full-height glass, slim frames and big rooflights for the most open rear room. Across County Durham we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Darlington, Hartlepool and Stockton-on-Tees.
Glass-led rear extensions in Darlington are planned around which way the garden faces, because that decides the glass specification. Terraces and semis are typical around County Durham. 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 glazed rear extension cost in County Durham?
In County Durham, our guide for a glazed rear extension is £2,520–£4,320 per square metre including VAT for a standard specification. 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) | £30,000–£52,000 |
| 4 m wide × 6 m deep (24 m²) | £60,500–£103,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
Do you need planning permission in County Durham?
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 County Durham 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 County Durham?
We cover 16 towns and districts in County Durham, including Darlington, Hartlepool and Stockton-on-Tees.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.