Castlereagh, County Down
Glazed rear extension in Castlereagh
Full-height glass, slim frames and big rooflights for the most open rear room. We design, get the approvals for and build glazed and glass-box rear extensions in Castlereagh and the surrounding area, with one contract from the first survey to building control sign-off.
We cover Castlereagh (BT8) as part of our County Down work. Glass-led rear extensions in Castlereagh are planned around which way the garden faces, because that decides the glass specification.
Book a free site visit
Tell us about the house and we'll call to arrange a free, no-obligation visit.
How much does a glazed rear extension cost in Castlereagh?
In Castlereagh, our guide for a glazed rear extension is £2,440–£4,180 per square metre including VAT for a standard specification. Northern Ireland prices are the lowest in our range.
| Size | Guide price inc VAT |
|---|---|
| 3 m wide × 4 m deep (12 m²) | £29,000–£50,000 |
| 4 m wide × 6 m deep (24 m²) | £58,500–£100,000 |
We put a fixed price in writing once the design is agreed, and explain any provisional sums such as foundations.
Do you need planning permission for a glazed rear extension in Castlereagh?
Planning for a glazed rear extension in Castlereagh follows the Northern Irish householder rules.
In Northern Ireland the Planning (General Permitted Development) Order (Northern Ireland) 2015 allows a single-storey rear extension of up to 3 metres on an attached house or 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary. Building control approval from the council is still required.
Insulation and glazing follow Technical Booklet F1 in Northern Ireland, checked by council building control.
Conservation areas, Areas of Outstanding Natural Beauty and listed buildings restrict permitted development in Northern Ireland. We check your house's planning history and any conservation area before drawing, so the route is clear before you spend on plans.
What are homes in Castlereagh like to extend?
Castlereagh has terraces near the centre, semis on the edges and many detached houses and bungalows in the surrounding countryside, where plots are often generous.
How a glazed rear extension in Castlereagh comes together
Survey visit
We visit free of charge, measure up, check access, drainage and neighbours' extensions, and note what you want the room to do.
Design and guide price
Two or three layout options with a guide price for each, so you choose the design knowing what it costs.
Approvals
Permitted development check or planning application, then building control drawings to the Northern Ireland Technical Booklets and structural calculations, plus a written agreement with neighbours for any shared-wall work.
Fixed price and build
A written price for the agreed design, a start date and a named contact through the build, ending with the building control completion certificate.
Glazed rear extensions near Castlereagh
Neighbouring places we cover include Belfast (2.3 miles) and Dundonald (3.7 miles).
- Glazed rear extension in Belfast
- Glazed rear extension in Dundonald
- Glazed rear extension in Holywood
- Glazed rear extension in Newtownabbey
- Glazed rear extension in Lisburn
Other work in Castlereagh:
FAQ
Glazed rear extension questions in Castlereagh
Do I need a party wall agreement?
Northern Ireland has no Party Wall Act; we agree any shared-wall work with your neighbour in writing.
Do I need planning permission for a rear extension in Castlereagh?
Often not for a single-storey rear extension of up to 3 metres (4 metres detached) under Northern Ireland's permitted development rules, outside conservation areas.
Will a glass extension be too hot?
Not if it is designed for its orientation, with solar-control glass, shading and ventilation.
Will I need a structural engineer?
Yes for the beam over the new opening and usually the foundations; we arrange them and their calculations go to building control.
How long does a rear extension take to build in Castlereagh?
Most single-storey rear extensions take 10 to 16 weeks on site and two-storey extensions 16 to 26 weeks, after design and approvals.
How much does a glazed rear extension cost in Castlereagh?
As a guide, £2,440–£4,180 per square metre including VAT for a standard specification. For example, 3 m wide × 4 m deep (12 m²): about £29,000–£50,000 at that rate. Your written price follows the survey.