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.
Cost is usually the first question about a single-storey extension, so here is the guide for Northern Ireland: £30,000–£64,000 including VAT. We cover the whole of County Armagh, with Craigavon, Portadown and Armagh among the main centres. Because each UK nation sets its own rules, we check the requirements in Northern Ireland for your property, then put a firm price on paper following a free survey.
- Guide price
- £30,000–£64,000 inc VAT
- Time on site
- 10–16 weeks on site
- Planning rules
- Northern Ireland
- Price level
- About 14% below the national guide
- Towns listed
- 3
- Survey
- Free, with a written quote
Single-storey extensions prices in County Armagh
What will a single-storey extension cost in County Armagh? 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 County Armagh |
|---|---|---|
| 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 |
Your price depends mostly on:
- Floor area, shape and number of corners
- Roof type, rooflights, lanterns and the amount of glazing
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
What do you get?
- Cavity walls built and insulated to building regulations
- 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
Homes in County Armagh
Armagh city has Georgian buildings, many in local limestone, around its historic centre. Portadown and Lurgan, linked by the Craigavon plan of the 1960s, have Victorian terraces, post-war estates and newer developments. The countryside is dotted with detached rural houses and bungalows, often finished in roughcast or render.
Rural bungalows and detached homes commonly take extensions, loft rooms, driveways and fencing. Terraces suit rear extensions and window replacement, and rendered houses often need re-rendering or painting.
A moderate inland climate with frequent rain and winter frost, and low ground near Lough Neagh can be wet.
Do you need permission in County Armagh?
Homes in County Armagh come under the regulations for Northern Ireland, summarised below. We don't rely on general rules alone: we confirm the position for your address with the council before a quote goes out.
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
Free site survey
We arrange a free site survey on a date convenient to you. We measure up, look at the existing structure and access, and discuss your plans for a single-storey extension so the price reflects your home.
Price and scope agreed
After the survey we send a quote for a single-storey extension that fixes the price for the scope we've agreed. If you want to change materials or scope, we revise it in writing before anything is booked.
Dates and permissions
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.
On site to finish
Our trades complete a single-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.
How we work
Frequently asked questions
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a single-storey extension, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
How much does a single-storey extension cost?
A typical single-storey rear extension of 15–25m² costs £30,000–£64,000, built to a plastered finish ready for your kitchen and decoration. As a guide, allow roughly £1,600–£2,800 per square metre plus fixed costs for groundworks, steelwork and fees. Smaller extensions cost more per square metre. The kitchen, flooring and large glazed doors are usually the biggest extras. We confirm a fixed price for the agreed specification after the survey.
How long does a single-storey extension take to build?
A single-storey extension usually takes 10–16 weeks on site, from digging foundations to final plastering. Bad weather, deep foundations or a complex roof can add time. Before work starts, allow several weeks for drawings, structural calculations and building control approval, and longer if planning permission is needed. We give you a stage-by-stage programme with your quote so you know what happens each week.
How long will a single-storey extension take?
On a typical home, allow 10–16 weeks on site. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
What does a typical extension build look like week by week?
A typical single-storey extension follows the same order: clearing the site and digging foundations, building walls up to roof level, then fitting the roof and windows to make it weathertight. Electrics, plumbing, insulation and plastering follow. The last stage is opening into the house, laying the screed and fitting doors and finishes. Building control inspects at key stages, and we book those visits for you.
Towns in County Armagh
We offer a single-storey extension in each of the towns below, all within County Armagh. Select yours for guide prices, postcodes covered and nearby places.