First-floor extensions in Bangor (County Down)

Useful details for planning a first-floor extension in Bangor (County Down).

Postcode districts: BT19 and BT20
County / area: County Down, Northern Ireland
Price region: Northern Ireland
Guide price: £22,000–£32,000 (£1,580–£2,290 per m²)
Approval route: It may be permitted development if it goes no more than 3 m beyond the original rear wall and stays 7 m from the rear boundary.
Nearest towns: Newtownards (4.8 miles), Donaghadee (5.5 miles), Holywood (6.4 miles)
First visit: Free, no obligation

About a first-floor extension

A first-floor extension suits you if your house already has a single-storey extension and you need more space upstairs. You get a structural check of the existing walls and foundations, a design that ties the new floor into the house, the approvals your nation needs, building regulations approval and the build, managed by us and carried out by vetted teams working under S&K.

Around Bangor (County Down) we also work in Newtownards, Donaghadee and Holywood, and across the rest of County Down. Postcode districts in and near Bangor (County Down): BT19 and BT20.

What it costs in Bangor (County Down)

Expect a first-floor extension in Bangor (County Down) to land somewhere around £22,000–£32,000 for 4 m × 3.5 m of new first-floor space (14 m²). Our Northern Ireland guide rate is £1,580–£2,290 per m², including VAT. We'll give you a written design-stage price first, then a fixed build price once the drawings are agreed.

Spec	Per m²	4 m × 3.5 m of new first-floor space (14 m²)
Essential	£1,460–£2,100 per m²	£20,500–£29,500
Standard	£1,580–£2,290 per m²	£22,000–£32,000
Premium	£1,900–£2,750 per m²	£26,500–£38,500

Planning and building control in Bangor (County Down)

In Northern Ireland, a first floor over a rear extension can be permitted development if the extension goes no more than 3 m beyond the original rear wall and stays at least 7 m from the rear boundary, with height, materials and roof pitch conditions. Over a side extension, or beyond these limits, a planning application costs £347 per dwelling.

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 Bangor (County Down) homes

Tying into the house

The new floor and walls must line up with the existing first floor, often through a new opening in the rear wall above the old one. Floor levels, the position of upstairs windows and the existing roof all affect where the opening can go, so we survey both floors carefully.

Can the existing structure take it?

Many single-storey extensions were built with foundations, walls and lintels sized for one storey. We find out what is there with trial holes and, where available, the original building control drawings. The engineer then decides whether to reuse, strengthen or rebuild parts of the structure.

How we'd run your project

Look at the house
We start in Bangor (County Down) with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
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.
Technical design
We prepare the building regulations drawings, structural calculations and specification so the build price can be fixed.
Finish and certify
Second fix, plastering and making good, then building control's final inspection and the completion paperwork.

Questions about first-floor extensions in Bangor (County Down)

Which postcodes do you cover around Bangor (County Down)?

We cover Bangor (County Down) (BT19 and BT20) and nearby places including Newtownards, Donaghadee and Holywood, plus the rest of County Down. The first site visit is free.

Who handles building control for a project in Bangor (County Down)?

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 a first-floor extension 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.

Can I build on top of my existing single-storey extension?

Often yes, but only after the structure has been checked. Foundations, walls and lintels built for one storey may not carry two. We dig trial holes, look for the original building control approval and ask the structural engineer to confirm what can stay, what needs strengthening and what must be rebuilt.

What happens to the room below while the first floor is built?

The old roof is removed, so the room below is exposed for a short period. We fit temporary weather protection, plan the work so the roof comes off only when the new structure is ready, and agree with you which rooms will be out of use and for roughly how long.

Nearby

The same service in neighbouring towns:

Other extensions in Bangor (County Down)

All two-storey extension services in Bangor (County Down) · First-floor extensions across County Down

Ready to talk it through? Call us or send the form and we'll arrange a visit to your home in Bangor (County Down).