First-floor extensions in Kilkeel

Quick reference for homeowners in Kilkeel.

Postcode districts: BT34
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: Warrenpoint (10.7 miles), Newcastle (11.7 miles), Newry (15.7 miles)
Distance to Bangor (County Down): about 43.5 miles
First visit: Free, no obligation

About a first-floor extension

A first-floor extension is a new upstairs room built on top of an existing single-storey part of your house, such as a rear kitchen extension, a utility or a side annexe. It adds a bedroom, bathroom or study without enlarging the footprint. Whether it works depends mainly on whether the walls and foundations below can carry the extra load.

We cover Kilkeel (BT34) and the places around it, including Warrenpoint (10.7 miles), Newcastle (11.7 miles) and Newry.

What it costs in Kilkeel

Most of the cost of a first-floor extension is set by its size and specification. For Kilkeel and the rest of Northern Ireland, our guide is £1,580–£2,290 per m² including VAT, so about £22,000–£32,000 for 4 m × 3.5 m of new first-floor space (14 m²). The fastest way to a firmer number is a free site visit, after which we price the design stage in writing.

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 Kilkeel

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 Kilkeel 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.

Escape and fire safety

A new first-floor bedroom needs an escape window with a clear opening of at least 0.33 m², at least 450 mm wide and 450 mm high, with the bottom no more than 1,100 mm above the floor, unless there is a protected route to the stairs.

How we'd run your project

Look at the house
We start in Kilkeel with a free visit: measurements, photos, a look at the loft and drains, and a frank chat about budget.
Design and approvals
We draw the extension and check it against the rules for Northern Ireland, then apply for planning permission or a certificate of lawfulness, whichever fits.
Price it properly
Once the engineer's calculations are in, we fix the build price in writing, with a clear list of what's included.
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 Kilkeel

Which postcodes do you cover around Kilkeel?

We cover Kilkeel (BT34) and nearby places including Warrenpoint, Newcastle and Newry, plus the rest of County Down. The first site visit is free.

How much does a first-floor extension cost in Kilkeel?

Our guide for Northern Ireland, which covers Kilkeel, is £1,580–£2,290 per m² including VAT. A typical project with 4 m × 3.5 m of new first-floor space (14 m²) comes to about £22,000–£32,000. Design and approval fees are extra, and we fix the build price in writing once the design is agreed.

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

Nearby towns we cover for first-floor extensions:

Other extensions in Kilkeel

All two-storey extension services in Kilkeel · First-floor extensions across County Down

Want a figure first? Try our guide price tool, then book a free visit to firm it up.