County Londonderry
Rear extensions for semi-detached houses in County Londonderry
Single or two-storey extensions for semi-detached houses, with side access and one party wall. Across County Londonderry we handle the whole rear extension: survey, drawings, the planning route, building control and the build. Towns we cover here include Derry~Londonderry, Coleraine and Limavady.
Semi-detached houses are common across County Londonderry, and their side access makes rear extensions quicker to build. Semis and detached houses are typical of County Londonderry, and many have room for a rear extension within Northern Ireland's permitted development limits.
How much does a semi-detached rear extension cost in County Londonderry?
In County Londonderry, our guide for a semi-detached rear extension is £1,650–£2,700 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) | £20,000–£32,500 |
| 4 m wide × 5 m deep (20 m²) | £33,000–£54,000 |
| 4 m wide × 6 m deep (24 m²) | £39,500–£64,500 |
Your written price follows a measured survey and an agreed design, so it reflects your house, not an average.
Do you need planning permission in County Londonderry?
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.
In Northern Ireland a rear extension of more than one storey can be permitted development if it projects no more than 3 metres and stays at least 7 metres from the rear boundary. Two-storey extensions in conservation areas, and most larger schemes, need planning permission from the council.
Northern Ireland has no larger-extension prior approval route; anything beyond permitted development needs a planning application.
Conservation areas, Areas of Outstanding Natural Beauty and listed buildings restrict permitted development in Northern Ireland.
Where in County Londonderry do we work?
FAQ
Questions people ask
Can I match pebbledash or render?
Yes. Many semis are refinished with new render across the whole back elevation so old and new match.
Single or two-storey on a semi?
Two-storey if you need bedrooms, single-storey if you need a bigger kitchen. Planning risk is lower for single-storey.
What if my neighbour has already extended?
That can make a matching depth easier to justify. We measure theirs at the survey.
Do you cover all of County Londonderry?
We cover 5 towns and districts in County Londonderry, including Derry~Londonderry, Coleraine and Limavady.
Who builds the extension?
Vetted building teams working under contract to us; your contract is with S&K Property Investments and Improvement Ltd.