Antrim house extensions
More space without moving: we plan and build extensions across Antrim, with one team for the drawings, the council and the build.
- Postcode districtsBT41
- Price regionNorthern Ireland (×0.86)
- Planning rulesNorthern Ireland
- Site visitFree, no obligation
Areas we cover around Antrim
Across BT41, we can visit, measure and advise. Neighbouring towns we cover include Ballymena (10 miles), Newtownabbey (13 miles), Belfast (14 miles), Lisburn (15 miles), Carrickfergus (16 miles). Just over the County Londonderry border, Magherafelt is about 17 miles away.
Planning and building control in Antrim
In Northern Ireland the Planning (General Permitted Development) Order 2015 lets some single-storey rear extensions go ahead without planning permission, up to 3 m on a semi-detached or terraced house and 4 m on a detached house, within height and boundary limits. Larger, side and two-storey extensions normally need planning permission from the council, and building control approval is separate.
In a conservation area or area of townscape character the permitted development rights are more limited, listed homes need listed building consent, and if rights have been removed by a condition, any extension needs an application.
Northern Ireland has no Party Wall Act. Where work is on or close to a shared boundary, we agree access and protection with your neighbour in writing before work starts.
Applications are decided by your council, which handles local planning in Northern Ireland.
What extensions cost in Antrim
Use these Antrim guide prices to sense-check a budget; the guide-price tool narrows them to your own size, and the site visit turns them into a written figure.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Single-storey rear extensions | 20 m² | £35,000 – £45,000 |
| Conservatory replacement extensions | 14 m² | £25,500 – £33,500 |
| Extensions over a garage | 12 m² | £21,500 – £28,000 |
| Side return extensions | 11 m² | £22,500 – £28,500 |
| Wraparound extensions | 25 m² | £49,000 – £62,500 |
| Double-storey extensions | 32 m² | £49,500 – £65,000 |
Choosing the right extension in Antrim
In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
For many houses here, single-storey rear extensions, bungalow extensions or side extensions gives the most useful space for the budget.
Choose an extension type
- Double-storey extensions · from £32,500
- Utility and boot room extensions · from £12,000
- Flat roof extensions · from £18,000
- Single-storey rear extensions · from £18,000
- Porch extensions · from £3,400
- Side extensions · from £18,500
- Bungalow extensions · from £22,500
- Extension plans and drawings · from £1,000
- Extensions over a garage · from £20,500
- Orangery extensions · from £25,500
- Timber frame extensions · from £18,000
- Wraparound extensions · from £30,500
- Annexe extensions · from £47,000
- Kitchen extensions · from £23,000
- Glass box extensions · from £25,500
- Conservatory replacement extensions · from £17,000
- Home office extensions · from £13,500
- Bedroom extensions · from £22,000
- Side return extensions · from £15,000
- Building regulations for extensions · from £750
- Planning permission for extensions · from £300
- Pitched roof extensions · from £19,000
Free site visit
We visit your Antrim home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions about extensions in Antrim
How much does an extension cost in Antrim?
Using our Northern Ireland factor (×0.86), a standard-spec single-storey extension of 20 m² is a guide £35,000 to £45,000 including VAT, and a 32 m² two-storey extension £49,500 to £65,000. Your written price follows the survey.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
How long does an extension take in Antrim?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Who do I contract with?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do I need planning permission for an extension in Antrim?
Not always. It depends on the size, position and your property's history. In Northern Ireland some single-storey rear extensions are permitted development; larger ones need planning permission.
Book a free site visit in Antrim
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.