County Down
Rear extensions for detached houses in County Down
Wider, deeper rear extensions with room for vaulted roofs and big glazing. Across County Down we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Bangor, Castlereagh and Newtownards.
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 detached house rear extension cost in County Down?
Guide prices for a detached house rear extension in County Down start from our Northern Ireland rate of £1,700–£2,780 per square metre, including VAT. Northern Ireland prices are the lowest in our range.
| Size | Guide price inc VAT |
|---|---|
| 4 m wide × 6 m deep (24 m²) | £40,500–£67,000 |
| 5 m wide × 8 m deep (40 m²) | £68,000–£111,500 |
These are guide ranges; the written quote after the survey is the figure that counts.
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.
Northern Ireland has no larger-extension prior approval route; anything beyond permitted development needs a planning application.
Northern Ireland's 2015 Order allows a two-storey rear extension of up to 3 metres where at least 7 metres is left to the rear boundary. Anything larger, or in a conservation area, needs a planning application to the council.
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
Can I have a vaulted ceiling?
Yes, with a pitched roof and exposed or boxed rafters, subject to the height limits.
Is an oak frame worth it?
It is a premium finish with a long life; it costs more than blockwork with a plain roof.
Does a big extension need more heating?
Usually yes. We size underfloor heating or new radiators to the room.
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.