Home extensions in Castlereagh
Looking to extend your home in Castlereagh? Start here: extension types, guide prices for Castlereagh, the planning rules that apply and how a project runs.
- Postcode districtsBT1, BT2, BT4, BT5, BT6, BT7
- Price regionNorthern Ireland (×0.86)
- Planning rulesNorthern Ireland
- Site visitFree, no obligation
Do extensions in Castlereagh need planning permission?
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.
Applications are decided by your council, which handles local planning in Northern Ireland.
Where we work near Castlereagh
Site visits are available across Castlereagh (BT1, BT2, BT4, BT5, BT6, BT7). Neighbouring towns we cover include Belfast (2 miles), Newtownabbey (6 miles), Lisburn (7 miles), Carrickfergus (10 miles), Antrim (16 miles). Newtownards, in County Down, is roughly 8 miles from Castlereagh and also on our list.
What works best for Castlereagh houses?
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.
Depending on the plot, annexe extensions and bungalow extensions are often the strongest options, with single-storey rear extensions worth considering where there is room.
Guide prices for Castlereagh
Every figure below is a guide for Castlereagh, adjusted for Northern Ireland build costs (×0.86) and including VAT. Design and council fees are shown separately on each page.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Wraparound extensions | 25 m² | £49,000 – £62,500 |
| Conservatory replacement extensions | 14 m² | £25,500 – £33,500 |
| Double-storey extensions | 32 m² | £49,500 – £65,000 |
| Single-storey rear extensions | 20 m² | £35,000 – £45,000 |
| Kitchen extensions | 20 m² | £36,000 – £46,000 |
Extension types and starting prices
- Wraparound extensions · from £30,500
- Bedroom extensions · from £22,000
- Porch extensions · from £3,400
- Side return extensions · from £15,000
- Annexe extensions · from £47,000
- Pitched roof extensions · from £19,000
- Single-storey rear extensions · from £18,000
- Extensions over a garage · from £20,500
- Side extensions · from £18,500
- Glass box extensions · from £25,500
- Building regulations for extensions · from £750
- Home office extensions · from £13,500
- Extension plans and drawings · from £1,000
- Utility and boot room extensions · from £12,000
- Timber frame extensions · from £18,000
- Orangery extensions · from £25,500
- Bungalow extensions · from £22,500
- Conservatory replacement extensions · from £17,000
- Kitchen extensions · from £23,000
- Planning permission for extensions · from £300
- Flat roof extensions · from £18,000
- Double-storey extensions · from £32,500
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
With the design and specification agreed, you get a fixed written price and a start date.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions about extensions in Castlereagh
How much does an extension cost in Castlereagh?
Using our Northern Ireland factor (×0.86), a standard-spec single-storey extension of 20 m² is a guide £35,000 to £45,000 including VAT, and a 32 m² two-storey extension £49,500 to £65,000. Your written price follows the survey.
Who do I contract with?
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.
Do I need planning permission for an extension in Castlereagh?
Not always. It depends on the size, position and your property's history. In Northern Ireland some single-storey rear extensions are permitted development; larger ones need planning permission.
How long does an extension take in Castlereagh?
Usually 2 to 4 months of design and approvals, then 10 to 16 weeks on site for a single-storey extension or 16 to 24 weeks for two storeys.
Do you cover all of Castlereagh?
Yes, including the surrounding parts of County Antrim. Site visits are free and there is no obligation.
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.