Extensions over a garage in Portstewart

Quick reference for homeowners in Portstewart.

Postcode districts: BT55
County / area: County Londonderry, 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: Portrush (2.7 miles), Coleraine (3.8 miles), Ballymoney (11.1 miles)
Distance to Derry: about 26.8 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 BT55 in and around Portstewart, along with neighbouring Portrush, Coleraine and Ballymoney.

What it costs in Portstewart

Guide prices for extensions over a garage in Northern Ireland are around £1,540–£2,240 per m² of new floor space, including VAT. For a typical project with 3 m × 6 m of new first-floor space (18 m²), that's roughly £27,500–£40,500. Professional fees for drawings and the structural engineer are listed separately on our prices page.

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 Portstewart

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 Portstewart 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.

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

Visit and first ideas
One of our team visits your house in Portstewart, checks the walls, roof and drains, and sketches out options with you.
Drawings, then consent
We draw the scheme, check it against the rules in Northern Ireland, and take it through the right consent with the council.
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 extensions over a garage in Portstewart

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

Our guide for Northern Ireland, which covers Portstewart, 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.

Who handles building control for a project in Portstewart?

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.

Which postcodes do you cover around Portstewart?

We cover Portstewart (BT55) and nearby places including Portrush, Coleraine and Ballymoney, plus the rest of County Londonderry. The first site visit is free.

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.

How do I get into a room over the garage?

Usually through a new opening off the existing landing or a bedroom, so the stairs stay where they are. If the floor levels do not match, a step or two may be needed inside the new room. Where a landing opening is not practical, a new stair from a converted garage is an option.

Nearby

The same service in neighbouring towns:

Other extensions in Portstewart

All two-storey extension services in Portstewart · Extensions over a garage across County Londonderry

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