What is a single-storey extension?
A single-storey extension is a ground-floor addition, usually at the rear of a house, that enlarges a kitchen, living or dining space. Most are built with cavity walls on concrete foundations and finished with a flat roof and roof lantern or a pitched tiled roof.
How much does a single-storey extension cost in Strabane?
In Strabane, a single-storey extension typically costs £1,700–£2,500 per m² of floor area, including VAT at 20% (standard rate). For a typical 20 m² project that is roughly £34,000–£50,000. That range is adjusted for Northern Ireland, where domestic building work typically costs around 14% below the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (14 m²) | £24,000–£35,000 |
| Typical project (20 m²) | £34,000–£50,000 |
| Larger project (28 m²) | £47,500–£70,000 |
| Rate per m² | £1,700–£2,500 |
The main things that change the cost:
- Glazing: sliding and bifold doors cost more than French doors
- How much of the existing house is opened up
- Roof type and the size of any lantern or roof windows
- Ground conditions and foundation depth
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a single-storey extension in Strabane?
The approval route for Strabane is set by planning law in Northern Ireland. In Northern Ireland the Planning (General Permitted Development) Order (Northern Ireland) 2015 allows single-storey rear extensions of up to 3 metres on attached houses and 4 metres on detached houses, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary. Houses with removed rights need planning permission, listed buildings need consent, and in conservation areas extensions must stay single-storey and must not come forward of the front or side walls.
In Northern Ireland building control approval comes from the council, usually through a full plans application or a building notice, with inspections during the work and a completion certificate at the end.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical single-storey extension we handle:
- First and second fix electrics, heating and plastering
- Cavity walls, insulation and roof to current building regulations
- Knock-through to the existing house with steel beams
- Measured survey and design drawings
- Building control inspections and completion certificate
- Structural calculations for steels and lintels
How long does it take?
The build itself usually takes 10 to 14 weeks on site for a typical rear extension, after approvals. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Strabane
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
From BT82 outwards, we take on projects throughout Strabane and the surrounding parts of County Tyrone.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about single-storey extensions in Strabane
Do I need planning permission for a single-storey extension in Strabane?
In Northern Ireland the Planning (General Permitted Development) Order (Northern Ireland) 2015 allows single-storey rear extensions of up to 3 metres on attached houses and 4 metres on detached houses, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary. Houses with removed rights need planning permission, listed buildings need consent, and in conservation areas extensions must stay single-storey and must not come forward of the front or side walls.
How much does a single-storey extension cost in Strabane?
In Strabane, a single-storey extension typically costs £1,700–£2,500 per m² of floor area, including VAT at 20% (standard rate). A typical 20 m² project comes to roughly £34,000–£50,000. Your fixed price depends on the survey and drawings.
Can I stay in the house during the build?
Usually yes. We build the shell before opening up the back wall, so the house stays weathertight for most of the job. There will be a few weeks when the kitchen or back room is out of use.
How long does a single-storey extension take in Strabane?
Typically 10 to 14 weeks on site for a typical rear extension, after approvals. Design and approvals beforehand usually take 6 to 12 weeks.
Is VAT charged on an extension?
Yes. Building work on an existing home is standard-rated, so VAT at 20% applies. Our guide prices include it.
What is a build-over agreement?
If a public sewer runs within 3 metres of the extension, the water company normally has to agree to the work before it starts. We check sewer records during design and apply where needed.