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 Craigavon?
In Craigavon, 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. The guide for Craigavon reflects typical costs in Northern Ireland, roughly 14% below the UK-wide figure. 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 |
The biggest cost drivers are:
- Scaffolding and access to the rear
- Total floor area across both floors
- Steel beams where walls are opened up
- Roof design and how it joins the existing roof
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a double-storey extension in Craigavon?
Before anything is built in Craigavon, we confirm which approvals apply 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.
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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
On a typical double-storey extension we handle:
- Design drawings and planning application
- Structural engineer’s calculations
- Foundations, drainage and scaffolding
- Opening up at both levels with steel beams
- Building control sign-off
- Windows, doors and staircase alterations
How long does it take?
The build itself usually takes 14 to 20 weeks on site, after planning and building control approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Craigavon
Across Northern Ireland, bungalows and chalet bungalows are common, so loft conversions and rear extensions are popular projects.
If your home is in Craigavon or close by in Portadown, Banbridge and Armagh, a free home visit is the first step.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about double-storey extensions in Craigavon
How much does a double-storey extension cost in Craigavon?
In Craigavon, 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.
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.
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.
Can I live at home during the work?
Most families stay put. The shell is built first and the house is opened up late in the job, so disruption inside is limited to a few weeks.
How long does a double-storey extension take in Craigavon?
Typically 14 to 20 weeks on site, after planning and building control approval. Design and approvals beforehand usually take 3 to 4 months.
Do I need planning permission for a double-storey extension in Craigavon?
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.