Flat roof extensions in Carrickfergus: design, approvals and build
Planning a flat roof extension in Carrickfergus? We survey the house, work out the planning route, draw the design and build it, so you deal with one team from the first visit to the completion certificate.
- Guide price in CarrickfergusFrom £18,000 inc VAT
- PlanningNI permitted development (rear 3–4 m) or planning
- Build time10–16 weeks on site
- Postcode districtsBT38
Extensions in and around Carrickfergus
Our survey diary covers Carrickfergus, including BT38. The same team covers Newtownabbey (6 miles), Larne (9 miles), Belfast (10 miles), Castlereagh (10 miles), all within easy reach.
For homes towards County Down, Bangor, County Down is around 7 miles away. Northern Ireland's housing ranges from city terraces to large numbers of detached houses and bungalows on rural plots, many in render, where single-storey extensions fit easily.
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.
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.
Building close to a public sewer needs the agreement of NI Water, which we check during design.
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.
Is a flat roof extension right for your house?
- Extensions under first-floor windows where a pitch will not fit
- Homeowners who want maximum light from above
- Modern and 1930s onwards houses
Height is often what decides a flat roof. Under first-floor windows, a pitched roof may not fit at all; a flat roof keeps the extension low while still giving a good ceiling height inside.
What should I budget for a flat roof extension in Carrickfergus?
For Carrickfergus we adjust our national guide rates by ×0.86, the factor we use for Northern Ireland. Figures include VAT; your written quote after the survey replaces them.
Typical rates in Carrickfergus: £1,500 to £2,880 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m 12 m² | £18,000 – £21,500 | £21,000 – £27,000 | £26,500 – £35,000 |
| 4 m × 5 m 20 m² | £30,000 – £35,500 | £35,000 – £45,000 | £44,500 – £58,000 |
| 5 m × 6 m 30 m² | £45,000 – £53,000 | £52,500 – £67,500 | £67,000 – £86,500 |
For a figure based on your own dimensions, use our guide-price tool.
What happens next
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
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
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a flat roof extension in Carrickfergus
Who do I contract with for a flat roof extension in Carrickfergus?
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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Carrickfergus, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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.
Can I walk on a flat roof extension?
Only for maintenance unless it is designed as a terrace. A roof terrace or balcony needs planning permission and a different structure.
Are flat roof extensions cheaper?
Usually slightly, because there is less roof structure and no tiles. Our guide range is about £1,500 to £2,880 per m² including VAT.
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.