Extensions over a garage in Belfast
Thinking about an extension over a garage in Belfast? We design it, take it through the approvals it needs and build it, with one team responsible from the first visit to the final certificate.
Useful details for planning an extension over a garage in Belfast.
- Postcode districts
- BT1, BT2, BT3, BT7, BT9, BT11 and nearby districts
- County / area
- County Antrim, Northern Ireland
- Price region
- Northern Ireland
- Guide price
- £27,500–£40,500 (£1,540–£2,240 per m²)
- Approval route
- Planning permission is needed: permitted development side extensions in Northern Ireland can't be more than 4 m high, which rules out two storeys.
- Nearest towns
- Castlereagh (2.3 miles), Newtownabbey (4.4 miles), Holywood (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 districts BT1, BT2, BT3, BT7, BT9, BT11 and nearby districts in and around Belfast, along with neighbouring Castlereagh, Newtownabbey and Holywood.
What it costs in Belfast
Most of the cost of an extension over a garage is set by its size and specification. For Belfast and the rest of Northern Ireland, our guide is £1,540–£2,240 per m² including VAT, so about £27,500–£40,500 for 3 m × 6 m of new first-floor space (18 m²). Kitchens, bathroom fittings and flooring are priced separately so you can compare like with like.
| Spec | Per m² | 3 m × 6 m of new first-floor space (18 m²) |
|---|---|---|
| Essential | £1,420–£2,060 per m² | £25,500–£37,000 |
| Standard | £1,540–£2,240 per m² | £27,500–£40,500 |
| Premium | £1,850–£2,690 per m² | £33,500–£48,500 |
Planning and building control in Belfast
In Northern Ireland, permitted development for two-storey work is set out for rear extensions, so building over a side garage normally needs a planning application, which costs £347 per dwelling. Councils aim for an average of 15 weeks for local applications. Building control approval is also needed, including fire separation if the garage stays in use.
Approval in Northern Ireland: Planning application for works to a house: £347. Councils aim to decide local applications within an average of 15 weeks; many take longer.
Building control: Building control approval from the local council under the Building Regulations (Northern Ireland), using the Technical Booklets.
Design points for Belfast homes
Floor levels and headroom
Garage floors are often lower than the house, and the new first floor may not line up with the existing landing. We set the floor level to avoid awkward steps upstairs, while keeping enough headroom in the garage below for a car or storage.
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
Start at your house
We come to your home in Belfast, measure up, check the ground floor walls and roof structure, and note anything near the boundaries.
Choose the approval route
Some designs fit permitted development, most need a householder application. We decide which applies in Northern Ireland 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
Foundations, walls, floor, roof, windows, then first and second fix. We break through into the house as late as we can.
Questions about extensions over a garage in Belfast
Who handles building control for a project in Belfast?
We handle it as part of the project. What's needed in Northern Ireland: building control approval from the local council under the Building Regulations (Northern Ireland), using the Technical Booklets. We prepare the drawings and the engineer's calculations, book the inspections and pass you the completion paperwork at the end.
How long does an extension over a garage take?
Allow 4 to 8 weeks for survey and design, then the approval period (councils aim to decide local applications within an average of 15 weeks; many take longer), 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 Belfast?
Belfast is in Northern Ireland. Planning permission is needed: permitted development side extensions in Northern Ireland can't be more than 4 m high, which rules out two storeys.
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
Other towns near Belfast:
Other extensions in Belfast
- Rear
- Side
- Wraparound
- Part two-storey
- First floor
- Semi-detached
- Detached
- Kitchen and bedrooms
- Bedroom and en-suite
All two-storey extension services in Belfast · Extensions over a garage across County Antrim
Book a free site visit in Belfast and we'll tell you what's possible, what approvals you need and what the design stage would cost.