Extensions over a garage in Carryduff

Before you start in Carryduff, here's what applies.

Postcode districts: BT8
County / area: County Down, 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 (3.8 miles), Belfast (5.7 miles), Lisburn (6 miles)
Distance to Bangor (County Down): about 13.2 miles
First visit: Free, no obligation

About an extension over a garage

An extension over a garage is a new first-floor room built on top of an existing attached garage, usually a bedroom, en-suite or study. It uses a footprint you already have, so it adds floor space without taking any garden. The garage walls and foundations often need strengthening or replacing to carry the new floor.

Carryduff sits about 13.2 miles from Bangor (County Down). Closer to home, Castlereagh is 3.8 miles away and Belfast 5.7 miles.

What it costs in Carryduff

Expect an extension over a garage in Carryduff to land somewhere around £27,500–£40,500 for 3 m × 6 m of new first-floor space (18 m²). Our Northern Ireland guide rate is £1,540–£2,240 per m², including VAT. The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

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 Carryduff

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 Carryduff homes

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.

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.

How we'd run your project

Look at the house
We start in Carryduff with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Get it approved
Once you're happy with the design we submit it to the council for Carryduff and deal with any questions from the planning officer.
Structure and building control
A structural engineer sizes the foundations and steels, and we get building regulations approval before work starts.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.

Questions about extensions over a garage in Carryduff

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.

Which postcodes do you cover around Carryduff?

We cover Carryduff (BT8) and nearby places including Castlereagh, Belfast and Lisburn, plus the rest of County Down. The first site visit is free.

How much does an extension over a garage cost in Carryduff?

Our guide for Northern Ireland, which covers Carryduff, is £1,540–£2,240 per m² including VAT. A typical project with 3 m × 6 m of new first-floor space (18 m²) comes to about £27,500–£40,500. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

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.

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.

Nearby

Nearby towns we cover for extensions over a garage:

Other extensions in Carryduff

All two-storey extension services in Carryduff · Extensions over a garage across County Down

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Carryduff.