Bedroom extensions in Castlereagh: design, approvals and build
From the first sketch to final sign-off, we plan and build bedroom extensions in Castlereagh and the surrounding County Antrim area.
- Guide price in CastlereaghFrom £22,000 inc VAT
- PlanningUsually needs planning permission
- Build time14–22 weeks on site
- Postcode districtsBT1, BT2, BT4, BT5, BT6
Who a bedroom extension suits
- Homeowners who want an en-suite master bedroom
- Growing families
- Multi-generational households
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.
Covering Castlereagh
Across BT1, BT2, BT4, BT5, BT6, BT7, we can visit, measure and advise. We also work in nearby Belfast (2 miles), Newtownabbey (6 miles), Lisburn (7 miles), Carrickfergus (10 miles).
For homes towards County Down, Newtownards is around 8 miles away. Northern Ireland's housing ranges from city terraces to large numbers of detached houses and bungalows on rural plots, many in render, where single-storey extensions fit easily.
Planning and approvals in Castlereagh
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
Bedroom extension prices in Castlereagh
Labour and material costs vary across the UK, so for Castlereagh we use our Northern Ireland factor (×0.86). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Castlereagh: £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.
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
We visit your Castlereagh home, measure up, talk through what you want and check the planning position.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
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.
Bedroom extension questions answered
Will my neighbours in Castlereagh 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.
Who do I contract with for a bedroom extension in Castlereagh?
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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Castlereagh, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
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.
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.
Book a free site visit in Castlereagh
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.