Extensions over a garage in Durham
Our extensions over a garage service in Durham covers everything: measured survey, design, planning or permitted development checks, structural design, building control and the build itself.
Before you start in Durham, here's what applies.
- Postcode districts
- DH1
- County / area
- County Durham, England
- Price region
- North East England
- Guide price
- £28,500–£41,500 (£1,580–£2,300 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 an extension over a garage
An extension over a garage suits you if you have an attached single garage beside the house and need an extra bedroom or a larger main bedroom with an en-suite. You get an inspection of the garage structure, a design that matches the house, the approvals your nation needs, structural design, building regulations approval and the build, carried out by vetted teams working under S&K.
We cover postcode district DH1 in and around Durham, along with neighbouring Brandon, Spennymoor and Chester-le-Street.
What it costs in Durham
Using our North East England rates, an extension over a garage with 3 m × 6 m of new first-floor space (18 m²) comes to about £28,500–£41,500, including VAT. Bigger or more glazed designs cost more per m². Steelwork for wide openings is the item most likely to move the figure; we'll know once the engineer has designed it.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,450–£2,110 per m² | £26,000–£38,000 |
| Standard | £1,580–£2,300 per m² | £28,500–£41,500 |
| Premium | £1,890–£2,750 per m² | £34,000–£49,500 |
Planning and building regulations in Durham
In England, most garages sit beside the house, so building over one makes a two-storey extension beyond a side wall, which always needs planning permission. If the garage is at the rear, the 3 m and 7 m rules for two-storey rear extensions apply, measured from the original house. A householder application costs £548 (or £575 for applications made from 8 December 2026).
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
Fire separation
If the garage stays a garage, the floor between it and the room above, and any door into the house, must give fire separation under building regulations. That usually means fire-resisting plasterboard ceilings, sealed gaps and a fire door, which we design in from the start.
Garage walls and the door opening
Garage walls are often a single skin of brick or block with piers, and the wide door opening needs a beam over it. Many over-garage extensions need new inner walls or a steel frame to carry the floor and to insulate properly, which we confirm before the design is fixed.
How we'd run your project
Free site visit
We visit your home in Durham, look at the structure, access and boundaries, and talk through what you want the new rooms to do.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in England before drawing in detail.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Build and sign-off
Vetted teams working under S&K build the extension, and we arrange the building control completion certificate at the end.
Questions about extensions over a garage in Durham
How long does an extension over a garage take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils should decide householder applications within 8 weeks of validation), then 4 to 8 weeks of technical design, which can overlap. The build itself usually takes 14 to 20 weeks, longer for large or complex designs.
Do I need planning permission for an extension over a garage 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.
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.
Do I need to convert the garage as well?
No. You can keep the garage for parking or storage and build only the room above, as long as the floor between them and any door into the house meet fire separation rules. Converting the garage at the same time is often good value, because the walls and foundations may be upgraded anyway.
Can my garage take a room on top?
Sometimes, but it needs checking. Many garages are built on shallow footings with thin walls, designed only for a single storey. We dig a trial hole and inspect the walls, and the structural engineer decides whether to reuse them, strengthen them, underpin the footings or build new foundations inside the garage.
Nearby
The same service in neighbouring towns:
Other extensions in Durham
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Durham · Extensions over a garage across County Durham
Want a figure first? Try our guide price tool, then book a free visit to firm it up.