What is a double-storey extension?
A double-storey extension (also called a two-storey extension) adds rooms on both the ground and first floor in one build. It typically gives a larger kitchen or living space downstairs and an extra bedroom or bathroom above.
How much does a double-storey extension cost in Limavady?
In Limavady, a double-storey extension typically costs £1,400–£2,150 per m² of floor area (both floors), including VAT at 20% (standard rate). For a typical 36 m² project that is roughly £50,500–£77,500. Building costs in Northern Ireland run about 14% below the UK average, and the figures for Limavady are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (25 m²) | £35,000–£54,000 |
| Typical project (36 m²) | £50,500–£77,500 |
| Larger project (50 m²) | £70,000–£107,500 |
| Rate per m² | £1,400–£2,150 |
What moves the price most:
- Scaffolding and access to the rear
- Roof design and how it joins the existing roof
- Bathrooms or en-suites on the first floor
- Brick matching and external finishes
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 double-storey extension in Limavady?
Here is how the rules work for a double-storey extension in Northern Ireland. In Northern Ireland an extension of more than one storey can be permitted development at the rear if it projects no more than 3 metres and is at least 7 metres from the rear boundary. Two-storey side extensions, and any in a conservation area, need planning permission.
Northern Ireland has no Party Wall Act. Work on shared walls relies on agreement with the neighbour and common law, so we agree the arrangements in writing before work starts.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
Handled as part of most double-storey extensions:
- Windows, doors and staircase alterations
- Opening up at both levels with steel beams
- Foundations, drainage and scaffolding
- Electrics, heating, plumbing and plastering
- Building control sign-off
- Brick or block walls, floors and a roof tied into the house
How long does it take?
Expect 14 to 20 weeks on site, after planning and building control approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Limavady
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
Limavady sits in County Londonderry, about 15 miles east of Derry. We cover the whole of Limavady, including postcodes BT49.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about double-storey extensions in Limavady
Will the first floor need a new staircase?
Not normally. The new rooms are reached from the existing landing, though a doorway or short corridor may need to be formed.
What drawings do I need?
Planning drawings for the application, then more detailed building regulations drawings and structural calculations for building control. We prepare both.
Do you build double-storey extensions in Limavady?
Yes. We build double-storey extensions across Limavady, including postcodes BT49. Every project starts with a free home visit.
Do I need planning permission for a double-storey extension in Limavady?
In Northern Ireland an extension of more than one storey can be permitted development at the rear if it projects no more than 3 metres and is at least 7 metres from the rear boundary. Two-storey side extensions, and any in a conservation area, need planning permission.
Is a double-storey extension cheaper per square metre?
Usually yes. You pay for one set of foundations and one roof but get two floors of space, so the cost per square metre is often lower than a single-storey extension.
How much does a double-storey extension cost in Limavady?
In Limavady, a double-storey extension typically costs £1,400–£2,150 per m² of floor area (both floors), including VAT at 20% (standard rate). A typical 36 m² project comes to roughly £50,500–£77,500. Your fixed price depends on the survey and drawings.