Durham, County Durham
Semi-detached rear extension in Durham
We plan and build rear extensions for semi-detached houses for homeowners in Durham. Single or two-storey extensions for semi-detached houses, with side access and one party wall. Start with a free site visit, then a written price once the design is agreed.
Durham sits in County Durham, with postcode districts including DH1. Semi-detached houses are common across County Durham, and their side access makes rear extensions quicker to build.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a semi-detached rear extension cost in Durham?
A semi-detached rear extension in Durham is priced at £1,710–£2,790 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 for a semi-detached rear extension in Durham?
The planning route for a semi-detached rear extension in Durham is set by England's householder rules and your council.
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.
England's rules allow a rear extension of more than one storey without an application only when it is no deeper than 3 metres and at least 7 metres from the boundary opposite the rear wall, and never on designated land. Most two-storey schemes need householder planning permission.
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. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Durham like to extend?
Brick terraces, colliery houses and post-war semis make up much of Durham. Former mining areas often need a coal mining risk check before foundations are designed.
How a semi-detached rear extension in Durham comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Planning and regulations
We take the design through the right planning route, then produce the construction drawings and engineer's calculations for building control.
Written price, then build
Once the design and approvals are in place, you get a fixed written price and programme, and we build through to sign-off.
Semi-detached rear extensions near Durham
Close by, we work in Spennymoor, about 5.5 miles away, and Chester-le-Street, about 5.7 miles away.
- Semi-detached rear extension in Spennymoor
- Semi-detached rear extension in Chester-le-Street
- Semi-detached rear extension in Hetton-le-Hole
- Semi-detached rear extension in Houghton-le-Spring
- Semi-detached rear extension in Stanley
Other work in Durham:
FAQ
Semi-detached rear extension questions in Durham
What postcode areas do you cover around Durham?
Including DH1, and the surrounding County Durham area.
Can I live at home while the extension is built?
Usually yes. Most of the work is outside until the back wall is opened near the end, and that stage is screened off.
How far can I extend a semi without planning?
3 metres under permitted development in England, or up to 6 metres with prior approval, outside designated land.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
Do you handle building control in Durham?
Yes. We apply to the council or a registered building control approver and hand over the completion certificate.
Do I need planning permission for a rear extension in Durham?
Often not for a single-storey rear extension of up to 3 metres (4 metres on a detached house) under permitted development, or up to 6 or 8 metres with prior approval, unless the house is in a conservation area or its rights have been removed.