A double-storey extension adds two floors of new space to your house in one build, typically a larger kitchen or living room downstairs with an extra bedroom, bathroom or en-suite above, sharing one set of foundations and one roof.
Whatever prompted you to look into a double-storey extension, whether wear and tear, a growing family or plans to move, we can survey your Newtownabbey home and give you a price in writing. Homes in Northern Ireland typically come in at £52,000–£103,000, VAT included, for this kind of work. We also cover Belfast, Carrickfergus and Castlereagh, and the same steps apply wherever you are in County Antrim.
- Guide price
- £52,000–£103,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- BT36 and BT37
- Planning rules
- Northern Ireland
- Local area
- County Antrim
- Survey
- Free, with a written quote
Double-storey extensions prices in Newtownabbey
No two jobs cost exactly the same, but the ranges below give a fair picture of a double-storey extension in Newtownabbey. Pricing for Northern Ireland runs about 14% below the national guide, and the overall guide is £52,000–£103,000 with VAT included. We'll confirm your figure after surveying the property for free.
| Type of job | What it usually involves | Guide in Newtownabbey |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £34,500–£56,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £52,000–£103,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £86,000–£155,000 |
The main things that change the figure:
- Combined floor area across both storeys
- Bathrooms, en-suites and plumbing on the upper floor
- Foundation depth, ground conditions and drains to divert
- Scaffolding duration, access and the level of finishes
What does the job include in Newtownabbey?
- Groundworks, foundations and below-ground drainage
- Insulated cavity walls with brick or render to match the house
- Scaffolding for the full build, erected and inspected
- Electrics, plumbing and heating by qualified trades, with certificates
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
Homes in County Antrim
Belfast has long rows of red-brick Victorian terraces, Edwardian villas in the north and south of the city and large post-war estates, while towns such as Ballymena, Antrim, Larne and Carrickfergus mix terraces, semis and newer developments. Dark basalt appears in older rural buildings, and pebbledash or roughcast is a very common finish.
Terraces suit loft conversions and rear extensions, and many need window and roof renewal. Pebbledashed homes commonly need re-rendering, and detached rural houses often take extensions, porches and driveways.
That mix of housing shapes how we approach a double-storey extension in Newtownabbey: the age and construction of your home affect the materials, the method and, in the end, the price.
Permissions for a double-storey extension in Newtownabbey
The notes below cover Northern Ireland, which is where Newtownabbey sits. Rules change and every property is different, so we speak to the council before pricing your job.
In Northern Ireland, two-storey extensions usually need planning permission from the council.
Building control approval is needed under the Building Regulations (Northern Ireland). There is no Party Wall Act in Northern Ireland.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
How does the job run?
A visit to your home
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
Quote in writing
You get the price in writing, itemised so you can see where the money goes. As long as the specification stays the same, that is the price you pay for a double-storey extension.
Plan and prepare
We handle the paperwork side: checking whether planning permission or building control approval is needed, submitting applications where they are, and scheduling the trades and materials around your dates.
The work itself
Our trades complete a double-storey extension while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
Why homeowners choose us
Questions about a double-storey extension in Newtownabbey
How much will a double-storey extension cost in Newtownabbey?
As a guide, expect to pay £52,000–£103,000 including VAT for a double-storey extension in Newtownabbey. That range is adjusted for Northern Ireland, which runs about 14% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
How is the new roof joined to the existing house?
The new roof is usually tied into the existing roof so the two read as one. On a rear extension this often means a lower ridge or a hipped end, with valleys where the slopes meet. We strip back some existing tiles, fix new rafters and battens, and lay matching tiles or slates. Lead or proprietary flashings seal the junctions so water runs off properly.
Can we live at home while it is built?
Most families stay at home during a double-storey extension. The new structure is built outside first, and we only break through into the existing rooms near the end, usually one floor at a time. Upstairs, this may mean a bedroom is out of use for a week or two. We fit dust screens, protect floors and stairs, and plan any time without water or power in advance.
Who do I deal with during the job?
One point of contact manages your project from survey to handover. They schedule the trades working under our contract, keep you updated on progress, and are the person to call with any question. You don't need to coordinate builders, electricians or decorators separately, because that is part of what we do.
How long does a double-storey extension take?
A double-storey extension typically takes 14–22 weeks on site, depending on size, roof design and weather. Foundations and ground-floor walls come first, then the first-floor joists, upper walls and roof. Once it is weathertight, electrics, plumbing, plastering and finishes follow. Allow extra time beforehand for drawings, calculations and approvals. We give you a stage-by-stage programme with your quote.
Nearby towns
Addresses in BT36 and BT37 are all covered for Newtownabbey, along with Belfast, Carrickfergus and Castlereagh close by. Give us your postcode when you get in touch and we will confirm the details.