Antrim bedroom extensions, designed and built
Thinking about a bedroom extension for your Antrim home? Start with a free site visit: we measure up, check what the council will allow and give you honest guide figures on the day.
- Guide price in AntrimFrom £22,000 inc VAT
- PlanningUsually needs planning permission
- Build time14–22 weeks on site
- Postcode districtsBT41

Covering 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).
For homes towards County Londonderry, Magherafelt is around 17 miles away. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
Is a bedroom extension right for your house?
- Multi-generational households
- Homeowners who want an en-suite master bedroom
- Growing families
New bedrooms on an upper floor need an escape window or a protected route to the outside under the building regulations. We design the window sizes and stair route to meet that from the outset.
What should I budget for a bedroom extension in Antrim?
Labour and material costs vary across the UK, so for Antrim we use our Northern Ireland factor (×0.86). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Antrim: £1,380 to £2,750 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| One bedroom 12 m² | £22,000 – £27,500 | £22,000 – £29,000 | £24,500 – £33,500 |
| Bedroom and en-suite 18 m² | £24,500 – £30,500 | £29,000 – £38,000 | £37,000 – £50,000 |
| Two rooms 30 m² | £41,000 – £50,500 | £49,000 – £63,500 | £61,500 – £83,000 |
For a figure based on your own dimensions, use our guide-price tool.
Do I need planning permission 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.
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.
Building close to a public sewer needs the agreement of NI Water, which we check during design.
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.
From first visit to completion
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
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 people ask about bedroom extensions
Will my neighbours in Antrim 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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Antrim, 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 I need building regulations approval in Antrim?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Does an en-suite need a window?
No, but it needs mechanical extraction that meets the building regulations. We design the duct route at the drawing stage.
Can I add a ground-floor bedroom for a relative?
Yes. A ground-floor bedroom with an accessible shower room is a common request. If it will be lived in as a self-contained home, planning treats it differently, so tell us how it will be used.
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.