Bedroom extensions in Lisburn: design, approvals and build
We design and build bedroom extensions for houses in Lisburn, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in LisburnFrom £22,000 inc VAT
- PlanningUsually needs planning permission
- Build time14–22 weeks on site
- Postcode districtsBT10, BT11, BT17, BT27, BT28
What is included
- En-suite drainage and ventilation design
- Layout options: two-storey, over-garage or ground floor
- Structure, roof, insulation and finish
- Heating extended to the new rooms
- Planning drawings and application
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.
Planning rules that apply in Lisburn
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.
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.
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.
Extensions in and around Lisburn
Across BT10, BT11, BT17, BT27, BT28, we can visit, measure and advise. Neighbouring towns we cover include Belfast (7 miles), Castlereagh (7 miles), Newtownabbey (11 miles), Antrim (15 miles).
Just over the County Down border, Newtownards is about 15 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 should I budget for a bedroom extension in Lisburn?
For Lisburn 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 Lisburn: £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.
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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
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
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Common questions in Lisburn
Will my neighbours in Lisburn 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 Lisburn, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a bedroom extension take to build in Lisburn?
On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
How much does a bedroom extension cost?
Our guide range is about £1,380 to £2,750 per m² including VAT. A bedroom with an en-suite of about 18 m² is typically £29,000 to £38,000 at standard spec, depending on whether it is part of a larger two-storey build.
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 Lisburn
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.