Side return extensions in County Durham
Our design and build teams take on side return extensions in County Durham, from the first measured survey through planning and building control to the finished room.
- Guide priceFrom £16,000 inc VAT
- PlanningOften permitted development; party wall notice usual
- Towns covered14
- Site visitFree, no obligation

Towns in County Durham
Local to County Durham
Towns we cover in County Durham include Darlington, Hartlepool, Stockton-on-Tees, Durham, Chester-le-Street, Billingham, Stanley, Consett. Across the North East, houses often have rear yards or modest gardens, so compact, well-lit single-storey extensions make the biggest difference.
How much does a side return extension cost in County Durham?
These guide figures apply our North East England adjustment (×0.91) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in County Durham: £1,910 to £3,460 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 1.8 m × 4.5 m 8 m² | £16,000 – £19,500 | £17,000 – £22,000 | £21,500 – £28,000 |
| 2 m × 5.5 m 11 m² | £21,000 – £25,500 | £24,000 – £30,500 | £30,000 – £38,500 |
| 2.2 m × 7 m 15 m² | £28,500 – £34,500 | £32,500 – £41,000 | £40,500 – £52,000 |
For a figure based on your own dimensions, use our guide-price tool.
Who a side return extension suits
- Homes where the garden is too small to lose much depth
- Narrow galley kitchens
- Victorian and Edwardian terraces with a rear outrigger
Planning rules that apply in County Durham
In England a single-storey side return infill is often permitted development if it stays within the height limits and is no wider than half the width of the original house. Conservation areas, listed buildings and flats always need an application, and the boundary wall usually brings in the Party Wall Act.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Side return extension questions answered
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for County Durham, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in County Durham be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Do you cover all of County Durham?
Yes, across the whole of County Durham. Site visits are free and there is no obligation.
Do side return extensions need planning permission?
In England many single-storey side returns fit within permitted development if they stay within the height limits and are no wider than half the width of the original house. Conservation areas, listed buildings and flats need an application. Other UK nations have their own rules, which we check.
Can I combine a side return with a rear extension?
Yes. That combination is a wraparound extension, which adds the most space to a terraced house.
Book a free site visit in County Durham
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.