Two-storey extensions in County Antrim
Whether you're in the biggest town in County Antrim or a village outside it, we can design, get approval for and build your extension.
County Antrim at a glance
- Nation
- Northern Ireland
- Price region
- Northern Ireland
- Postcode areas
- BT
- Main town
- Belfast
- Towns listed
- 15
- Site visits
- Free, no obligation
Choose your town
- Belfast
- Lisburn
- Newtownabbey
- Castlereagh
- Carrickfergus
- Ballymena
- Antrim
- Larne
- Ballymoney
- Ballyclare
- Ballycastle
- Jordanstown
- Randalstown
- Crumlin (County Antrim)
- Greenisland
Guide prices in Northern Ireland
| Extension type | Per m² | Typical project |
|---|---|---|
| Two-storey rear extension | £1,760–£2,380 per m² | £49,500–£66,500 |
| Two-storey side extension | £1,800–£2,420 per m² | £76,000–£101,500 |
| Two-storey wraparound extension | £1,890–£2,600 per m² | £106,000–£145,500 |
| Part single, part two-storey | £1,760–£2,420 per m² | £63,500–£87,000 |
| Extension over a garage | £1,540–£2,240 per m² | £27,500–£40,500 |
| First-floor extension over an existing single storey | £1,580–£2,290 per m² | £22,000–£32,000 |
| Two-storey front extension | £1,940–£2,640 per m² | £23,000–£31,500 |
Including VAT, Standard spec. See all prices and fees.
Across County Antrim we cover Belfast (BT1), Lisburn (BT10), Newtownabbey (BT36), Castlereagh (BT4), Carrickfergus (BT38), Ballymena (BT42), Antrim (BT41) and Larne (BT40), plus the smaller places around them.
Which type suits your house?
If you're not sure which type fits, that's what the free visit is for. We'll sketch the realistic options for your house in County Antrim, with a rough idea of the approval route and cost for each.
The rules in Northern Ireland
County Antrim is in Northern Ireland. Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Most others need planning permission. Planning application for works to a house: £347. Councils aim to decide local applications within an average of 15 weeks; many take longer.
The full Northern Ireland rules explained
Extension types
- Two-storey rear extensions
- Two-storey side extensions
- Two-storey wraparound extensions
- Part single, part two-storey extensions
- Extensions over a garage
- First-floor extensions
- Two-storey front extensions
By house type
- Two-storey extensions for semi-detached houses
- Two-storey extensions for detached houses
- Two-storey extensions for end-of-terrace houses
Rooms and uses
- Kitchen extensions with bedrooms above
- Extra bedroom and en-suite extensions
- Two-storey annexe extensions
- Garage conversions with a room above
Design and approvals
- Two-storey extension plans and drawings
- Planning permission for two-storey extensions
- Structural engineering for two-storey extensions
- Building regulations for two-storey extensions
- Design and build two-storey extensions
Questions about extensions in County Antrim
How much does a two-storey extension cost in County Antrim?
In Northern Ireland our guide for a two-storey rear extension is £1,760–£2,380 per m² including VAT, about £49,500–£66,500 for a 4 m × 3.5 m footprint on two floors (28 m² of new floor space). Side and wraparound extensions cost a little more per m².
Do I need planning permission in County Antrim?
Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Most others need planning permission. Planning application for works to a house: £347.
Do you cover the whole of County Antrim?
Yes. We list the main towns here, but we cover the whole of County Antrim including villages. The first site visit is free.
What happens at the first visit?
We look at your house, the boundaries, access and drains, talk through what you need and explain the approvals. Then we price the design stage, including the measured survey, in writing.