Derry/Londonderry bedroom extensions, designed and built
Planning a bedroom extension in Derry/Londonderry? 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 Derry/LondonderryFrom £22,000 inc VAT
- PlanningUsually needs planning permission
- Build time14–22 weeks on site
- Postcode districtsBT48
Extensions in and around Derry/Londonderry
Site visits are available across Derry/Londonderry (BT48). Nearby, we also take on projects in Limavady (15 miles), Coleraine (27 miles), Magherafelt (31 miles).
Strabane, in County Tyrone, is roughly 13 miles from Derry/Londonderry and also on our list. In Northern Ireland, extension projects follow the NI planning rules and council building control, which we account for from the first survey.
What we take care of
- Fire safety: escape windows and smoke alarms to building regulations
- En-suite drainage and ventilation design
- Heating extended to the new rooms
- Planning drawings and application
- Layout options: two-storey, over-garage or ground floor
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.
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.
Building close to a public sewer needs the agreement of NI Water, which we check during design.
Applications are decided by your council, which handles local planning in Northern Ireland.
Bedroom extension prices in Derry/Londonderry
Labour and material costs vary across the UK, so for Derry/Londonderry we use our Northern Ireland factor (×0.86). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Derry/Londonderry: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
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
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.
Common questions in Derry/Londonderry
Will my neighbours in Derry/Londonderry 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.
Do you cover all of Derry/Londonderry?
Yes. We cover Derry/Londonderry and the surrounding parts of County Londonderry. Site visits are free and there is no obligation.
How long does a bedroom extension take to build in Derry/Londonderry?
On site, typically 14 to 22 weeks once approvals are in place. Before that, allow 8–14 weeks design and approvals.
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 Derry/Londonderry
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.