First-floor extensions in Ballymena

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

Postcode districts: BT42, BT43 and BT44
County / area: County Antrim, 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: Randalstown (7.9 miles), Antrim (10.4 miles), Ballyclare (13.5 miles)
Distance to Belfast: about 23.1 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 Ballymena (BT42, BT43 and BT44) and the places around it, including Randalstown (7.9 miles), Antrim (10.4 miles) and Ballyclare.

What it costs in Ballymena

Guide prices for first-floor extensions in Northern Ireland are around £1,580–£2,290 per m² of new floor space, including VAT. For a typical project with 4 m × 3.5 m of new first-floor space (14 m²), that's roughly £22,000–£32,000. 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 Ballymena

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 Ballymena homes

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.

Replacing the flat roof

The existing roof usually comes off and is replaced by a new first-floor structure. The room below is exposed for a short time, so we plan temporary weatherproofing and sequence the work to keep the kitchen or living room usable for as long as possible.

How we'd run your project

Measure and listen
A visit to Ballymena to understand how you live in the house now and what the extra rooms need to do, plus a first look at the structure.
Drawings and permission
Our designers produce plans and elevations, then we take care of planning or permitted development checks with the council covering Ballymena.
Fixed price in writing
With approved drawings and calculations, we give you a fixed build price and a programme you can plan around.
Build it
The new structure goes up first, then we open into the house, finish inside and get the completion certificate.

Questions about first-floor extensions in Ballymena

Which postcodes do you cover around Ballymena?

We cover Ballymena (BT42, BT43 and BT44) and nearby places including Randalstown, Antrim and Ballyclare, plus the rest of County Antrim. The first site visit is free.

Who handles building control for a project in Ballymena?

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.

Do I need planning permission for a first-floor extension in Ballymena?

Ballymena is in Northern Ireland. 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.

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 Ballymena

All two-storey extension services in Ballymena · First-floor extensions across County Antrim

Send us your postcode and a few details. We'll get back to you to arrange a visit and talk through your options.