Carrickfergus side extensions, designed and built
From the first sketch to final sign-off, we plan and build side extensions in Carrickfergus and the surrounding County Antrim area.
- Guide price in CarrickfergusFrom £18,500 inc VAT
- PlanningDepends on the NI limits; checked at the survey
- Build time10–18 weeks on site
- Postcode districtsBT38
Guide prices for Carrickfergus
Prices below are for Carrickfergus, using the Northern Ireland factor of ×0.86. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Carrickfergus: £1,500 to £2,920 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £18,500 – £23,000 | £21,000 – £27,500 | £26,500 – £35,500 |
| 3 m × 6 m 18 m² | £27,000 – £33,000 | £31,500 – £41,500 | £40,000 – £53,000 |
| 3 m × 8 m 24 m² | £36,000 – £43,500 | £42,000 – £55,000 | £53,500 – £70,500 |
Try the guide-price tool to see a range for your own size and finish.
Working in Carrickfergus
Across BT38, we can visit, measure and advise. We also work in nearby Newtownabbey (6 miles), Larne (9 miles), Belfast (10 miles), Castlereagh (10 miles).
In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
Planning and approvals in Carrickfergus
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.
The planning position for a specific Carrickfergus address depends on its history and any designations, which is why we check it at the first visit.
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.
Included in a typical project
- New openings through the side wall
- Structure, roof tied into the house
- Planning route checked or application made
- Windows, doors and finishes to match
- Survey, design and street-view drawings
- Foundations near boundaries and any drains
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Carrickfergus
How long does a side extension take to build in Carrickfergus?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Will my neighbours in Carrickfergus be involved?
If a planning application is needed, the council notifies neighbours. Where work is close to a shared boundary, we agree access and protection with them in writing.
Do you cover all of Carrickfergus?
Yes. We cover Carrickfergus and the surrounding parts of County Antrim. Site visits are free and there is no obligation.
How much does a side extension cost?
Our guide range is about £1,500 to £2,920 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £31,500 to £41,500 in Carrickfergus.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
Book a free site visit in Carrickfergus
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.