Annexe extensions in Magherafelt: design, approvals and build
A annexe extension in Magherafelt starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in MagherafeltFrom £47,000 inc VAT
- PlanningUsually needs planning permission
- Build time16–24 weeks on site
- Postcode districtsBT45
Planning rules that apply in Magherafelt
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.
Who an annexe extension suits
- Relatives who need support close by
- Homes with a large side or rear garden
- Multi-generational families
Accessibility is cheaper to design in than to retrofit. Level access, a 900 mm door width, a level-access shower and space to turn a wheelchair can all be planned into the footprint for little extra cost.
Guide prices for Magherafelt
Prices below are for Magherafelt, using the Northern Ireland factor of ×0.86. They are guide ranges including VAT for the build only, not a quote.
Typical rates in Magherafelt: £1,720 to £3,270 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £47,000 – £59,500 | £51,500 – £64,500 | £64,500 – £82,000 |
| One-bedroom annexe 35 m² | £60,000 – £75,500 | £72,000 – £90,500 | £90,000 – £114,500 |
| Larger annexe 45 m² | £77,000 – £97,000 | £92,500 – £116,500 | £116,000 – £147,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Covering Magherafelt
Postcode districts we cover around Magherafelt include BT45. We also work in nearby Limavady (23 miles), Coleraine (26 miles), Derry/Londonderry (31 miles).
For homes towards County Tyrone, Cookstown is around 9 miles away. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
Once the layout is agreed, we deal with the council: planning permission or written confirmation that none is needed, plus building control.
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
The build is managed from start to finish, inspected at each stage and signed off on completion.
Annexe extension questions answered
How long does an annexe extension take to build in Magherafelt?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Magherafelt, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Will my neighbours in Magherafelt 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.
How much does an annexe extension cost?
Our guide range is about £1,720 to £3,270 per m² including VAT. A one-bedroom annexe of about 35 m² is typically £72,000 to £90,500 at standard spec in Magherafelt.
Does an annexe extension need planning permission?
Usually yes, because of its size and the way it will be used. Councils check that it stays ancillary to the main house, so the application must describe the use clearly.
Book a free site visit in Magherafelt
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.