Side extensions for homes in County Durham
A side extension in County Durham starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide priceFrom £20,000 inc VAT
- PlanningSingle storey can be permitted development
- Towns covered14
- Site visitFree, no obligation
Towns in County Durham
What is included
- New openings through the side wall
- Structure, roof tied into the house
- Planning route checked or application made
- Windows, doors and finishes to match
- Survey, design and street-view drawings
Extensions in and around 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.
Planning and approvals in County Durham
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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).
Side extension prices in County Durham
Labour and material costs vary across the UK, so for County Durham we use our North East England factor (×0.91). The ranges include VAT and exclude design, structural and council fees.
Typical rates in County Durham: £1,590 to £3,090 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £20,000 – £24,500 | £22,000 – £29,000 | £28,000 – £37,500 |
| 3 m × 6 m 18 m² | £28,500 – £34,500 | £33,500 – £43,500 | £42,500 – £56,000 |
| 3 m × 8 m 24 m² | £38,000 – £46,000 | £44,500 – £58,000 | £56,500 – £74,500 |
For a figure based on your own dimensions, use our guide-price tool.
How the project works
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Your questions about a side extension in County Durham
How long does a side extension take to build in County Durham?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Who do I contract with for a side extension in County Durham?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do I need building regulations approval in County Durham?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I build a side extension without planning permission?
In England a single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a planning application.
How much does a side extension cost?
Our guide range is about £1,590 to £3,090 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £33,500 to £43,500 in County Durham.
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.