A single-storey extension is a new ground-floor room built onto your house, usually at the rear or side, with its own foundations, walls and roof, creating a bigger kitchen, living space or bedroom without moving home.
Planning a single-storey extension for a home in Bangor, County Down means making a handful of decisions about materials, layout, finish and timing. We help you work through them at a free survey, then confirm in writing what it will cost for the options you pick. Most projects of this type need 10–16 weeks on site, and we cover every BT19 and BT20 address as well as the rest of County Down.
- Guide price
- £30,000–£64,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- BT19 and BT20
- Planning rules
- Northern Ireland
- Local area
- North Down
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Bangor, County Down?
What will a single-storey extension cost in Bangor, County Down? Our guide range is £30,000–£64,000 including VAT. That figure is adjusted for Northern Ireland, about 14% below the national guide, and is intended for planning a budget. A firm written price for your chosen specification follows a free survey at your home.
| Type of job | What it usually involves | Guide in Bangor |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £19,000–£34,500 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £30,000–£64,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £60,000–£112,000 |
Expect these to shape the final quote:
- Floor area, shape and number of corners
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Finishes, kitchen, flooring and heating specification
Scope of the work
- Groundworks, foundations and below-ground drainage
- Steel beams to open into the existing house
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Building in Bangor, County Down
County Down takes in suburbs of Belfast, Bangor and Holywood with Victorian and Edwardian villas, and Newry, Downpatrick and Banbridge with older town centres and newer estates. Mourne granite appears in buildings around the mountains, and detached rural homes and bungalows are common across the county, often rendered or pebbledashed.
Villas and semis suit kitchen extensions, loft conversions and garden landscaping. Rural detached homes commonly take extensions and driveways, and rendered houses often need re-rendering, roofline renewal and window replacement.
None of this holds for every street in Bangor, County Down, which is why we look at your actual house before pricing a single-storey extension rather than assuming from its age alone.
Do you need permission in Bangor, County Down?
Bangor, County Down is in Northern Ireland, so the planning and building rules set out below are the ones that apply. We confirm the details with the council before we quote.
In Northern Ireland, permitted development allows many single-storey rear extensions, typically up to 3 m deep on attached houses and 4 m on detached houses, within height and garden-coverage limits. Conservation areas, listed buildings and side extensions are more restricted.
Building control approval under the Building Regulations (Northern Ireland) is needed for extensions. Northern Ireland has no Party Wall Act, so boundary work is agreed with neighbours directly.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
The four stages
A visit to your home
We begin by looking at the job in person. During the free survey we discuss options, materials and budget for a single-storey extension, and photograph or measure anything the quote needs to reflect.
Your fixed price
The quote arrives in writing, not over the phone. It covers the full scope, the finishes you've chosen, any exclusions and the payment schedule, with a fixed price tied to that specification.
Booking the work
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
The work itself
On site, the agreed plan is followed and any change is put in writing first. At completion we do a final clean, go through the snagging list with you and leave you with the relevant documents.
Working with SK Home Improvements
Common questions
What is the Party Wall Act and does it apply to me?
The Party Wall etc. Act 1996 applies in England and Wales only. In England and Wales, it requires you to give notice to neighbours before certain work on or near a shared wall, such as digging foundations within 3m of their building and deeper than its footings. Neighbours can agree or appoint a surveyor. Scotland and Northern Ireland have no equivalent Act, though general rights still apply. We identify whether notices are needed during the survey.
Is a flat roof or a pitched roof better on an extension?
A flat roof is quicker to build and usually costs less, gives a clean modern look and works well with a roof lantern. A pitched roof matches the main house, sheds water faster and allows a vaulted ceiling, but it costs more and its height can affect neighbours. Modern flat roofs in EPDM rubber or GRP last well when properly detailed. Planning rules on height can also decide the choice.
Can you combine a single-storey extension with other work?
Yes. Because we manage several trades under one contract, we can plan a single-storey extension alongside other work on your Bangor, County Down home, such as new windows with rendering, or a kitchen refit with an extension. Combining jobs can reduce repeat set-up such as scaffolding, skips and access, and every element is listed and priced in the same written quote.
Can we stay at home during the build?
Most people stay at home while we build a single-storey extension, because the new structure goes up outside before we break through. The disruptive part is usually the last few weeks, when we open into the house and fit the kitchen. We put up dust screens, keep a safe route through the house and agree a temporary kitchen setup if needed. Water and power are only off for short, planned periods.
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
Nearby towns
Live in Bangor, County Down? Our coverage takes in the BT19 and BT20 postcode areas and reaches out to Newtownards, Carrickfergus and Newtownabbey, so homes on the outskirts and in the next town along are included.