County Down
Glazed and glass-box rear extensions in County Down
Full-height glass, slim frames and big rooflights for the most open rear room. Rear extensions in County Down: we cover 8 towns including Bangor, Castlereagh and Newtownards, with design, approvals and the build under one contract.
Glass-led rear extensions in Bangor are planned around which way the garden faces, because that decides the glass specification. Semis and detached houses are typical of County Down, and many have room for a rear extension within Northern Ireland's permitted development limits.
How much does a glazed rear extension cost in County Down?
A glazed rear extension in County Down is priced at £2,440–£4,180 per square metre including VAT as a guide, before kitchen fit-out and fees. 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 |
Ground conditions, glazing, the roof and how far the house is opened up move the final figure within the range.
Do you need planning permission in County Down?
Northern Ireland's permitted development rules allow a single-storey rear extension of 3 metres on terraced and semi-detached houses and 4 metres on detached houses, with a 4 metre height limit. Listed buildings, conservation areas and houses with removed rights need planning permission from the council.
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.
Where in County Down do we work?
FAQ
Questions people ask
Will a glass extension be too hot?
Not if it is designed for its orientation, with solar-control glass, shading and ventilation.
Sliding or bifold doors?
Sliders give bigger panes and slimmer sightlines; bifolds open the whole width. Our guide compares them.
Can I have a level threshold?
Yes, with a drainage channel outside the doors and the slab set to the patio level.
Do you cover all of County Down?
We cover 8 towns and districts in County Down, including Bangor, Castlereagh and Newtownards.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.