Annexe extensions for homes in Coleraine
Coleraine homeowners can use us for the whole annexe extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in ColeraineFrom £47,000 inc VAT
- PlanningUsually needs planning permission
- Build time16–24 weeks on site
- Postcode districtsBT52
How much does an annexe extension cost in Coleraine?
Labour and material costs vary across the UK, so for Coleraine we use our Northern Ireland factor (×0.86). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Coleraine: £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 |
For a figure based on your own dimensions, use our guide-price tool.
Will the council need to approve it?
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.
Homes in conservation areas, areas of townscape character and listed buildings have tighter rules, so we always check the property's status and planning history before design starts.
In Northern Ireland building control is run by the councils under the Building Regulations (Northern Ireland). We submit full plans or a building notice and book the inspections through to completion.
Applications are decided by your council, which handles local planning in Northern Ireland.
What we take care of
- Kitchenette, shower room and bedroom finish
- Separate or shared heating and hot water
- Fire separation and alarms to building regulations
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Planning application describing ancillary use
Covering Coleraine
Across BT52, we can visit, measure and advise. Neighbouring towns we cover include Limavady (13 miles), Magherafelt (26 miles), Derry/Londonderry (27 miles).
For homes towards County Antrim, Ballymena is around 24 miles away. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Your questions about an annexe extension in Coleraine
Do you cover all of Coleraine?
Yes. We cover Coleraine and the surrounding parts of County Londonderry. Site visits are free and there is no obligation.
Who do I contract with for an annexe extension in Coleraine?
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.
How long does an annexe extension take to build in Coleraine?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Can the annexe have its own front door?
Yes, many do, but it should still connect to the main house to stay clearly part of it.
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 Coleraine
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.