Two-storey side extensions in Durham
Adding a two-storey side extension in Durham gives you two new rooms stacked on one footprint. Here's how we'd approach it, what it typically costs and the rules that apply in England.
Useful details for planning a two-storey side extension in Durham.
- Postcode districts
- DH1
- County / area
- County Durham, England
- Price region
- North East England
- Guide price
- £77,500–£104,000 (£1,840–£2,480 per m²)
- Approval route
- Planning permission is needed: in England, permitted development only allows single-storey extensions to the side.
- Nearest towns
- Brandon (2.5 miles), Spennymoor (5.5 miles), Chester-le-Street (5.7 miles)
- Distance to Darlington
- about 17.5 miles
- First visit
- Free, no obligation
About a two-storey side extension
A two-storey side extension is a new two-floor addition built into the space beside your house, often over a driveway or side passage. It typically adds one or two bedrooms upstairs and a utility, study or larger kitchen below, without giving up rear garden.
We cover postcode district DH1 in and around Durham, along with neighbouring Brandon, Spennymoor and Chester-le-Street.
What it costs in Durham
For budgeting in Durham, allow around £77,500–£104,000 for a two-storey side extension with a 3 m × 7 m footprint on two floors (42 m² of new floor space). That's based on £1,840–£2,480 per m² including VAT for North East England. Keep a contingency of around 10% for things nobody can see until the ground is opened up.
| Spec | Per m² | A 3 m × 7 m footprint on two floors (42 m² of new floor space) |
|---|---|---|
| Essential | £1,700–£2,280 per m² | £71,500–£95,500 |
| Standard | £1,840–£2,480 per m² | £77,500–£104,000 |
| Premium | £2,210–£2,970 per m² | £93,000–£124,500 |
Planning and building regulations in Durham
In England, a two-storey side extension always needs householder planning permission, because permitted development only allows single-storey extensions beyond a side wall. The fee is £548 (or £575 for applications made from 8 December 2026), and councils should decide within 8 weeks of validation. Expect them to look at set-back, roof height, gaps to the boundary and the effect on neighbours.
Approval in England: Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
Building regulations: Building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end.
Design points for Durham homes
Access and services
Side extensions often cover the only route to the back garden, a gas meter, soil pipes or a drain run. We plan bin and bike access, move meters and pipes where needed and check drains early, because these items affect both cost and layout.
Set-down and set-back
Councils usually want a two-storey side extension to look subordinate to the house. Setting the front wall back from the main front and dropping the ridge slightly below the main roof helps it read as an addition, and is often expected in local design guidance.
How we'd run your project
Measure and listen
A visit to Durham to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Get it approved
Once you're happy with the design we submit it to the council for Durham and deal with any questions from the planning officer.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about two-storey side extensions in Durham
Who handles building regulations for a project in Durham?
We handle it as part of the project. What's needed in England: building regulations approval (full plans recommended) from the council or a registered building control approver, with a completion certificate at the end. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
Which postcodes do you cover around Durham?
We cover Durham (DH1) and nearby places including Brandon, Spennymoor and Chester-le-Street, plus the rest of County Durham. The first site visit is free.
How much does a two-storey side extension cost in Durham?
Our guide for North East England, which covers Durham, is £1,840–£2,480 per m² including VAT. A typical project with a 3 m × 7 m footprint on two floors (42 m² of new floor space) comes to about £77,500–£104,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.
Do I need planning permission for a two-storey side extension in Durham?
Durham is in England, so England planning rules apply. Planning permission is needed: in England, permitted development only allows single-storey extensions to the side. If in doubt, a lawful development certificate or a planning application gives you certainty before you build.
Can I build a two-storey side extension over my driveway?
Yes, if the drive is wide enough for a useful room and the council accepts the design. You may lose off-road parking, which some councils weigh up, and the foundations need to suit the ground below. We check parking, drains and meter positions at the free site visit before any drawings are prepared.
Nearby
We also cover places near Durham, including:
Other extensions in Durham
- Rear
- Wraparound
- Part two-storey
- Over a garage
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Durham · Two-storey side extensions across County Durham
The quickest next step is a visit. We'll look at your house in Durham and give you an honest view of the options.