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.
We offer a single-storey extension throughout County Durham, from Darlington, Hartlepool, Stockton-on-Tees and Durham to the smaller places in between. Each project starts with a free survey at your home and ends with a written figure, fixed for the work you choose. Because County Durham is in England, we work to the planning system and building standards used there, and guide prices for the North East run at £31,500–£68,000 including VAT.
- Guide price
- £31,500–£68,000 inc VAT
- Time on site
- 10–16 weeks on site
- Planning rules
- England
- Price level
- About 10% below the national guide
- Towns listed
- 12
- Survey
- Free, with a written quote
How much does a single-storey extension cost in County Durham?
Use the table to gauge the cost of a single-storey extension in County Durham before we visit. Figures include VAT and are scaled for the North East, coming out about 10% below the national guide, which gives £31,500–£68,000 overall. After a free survey, you receive a fixed written price.
| Type of job | What it usually involves | Guide in County Durham |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £20,000–£36,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £31,500–£68,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £63,000–£117,000 |
What moves the price up or down:
- Floor area, shape and number of corners
- Roof type, rooflights, lanterns and the amount of glazing
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What’s included?
- Groundworks, foundations and below-ground drainage
- Cavity walls built and insulated to building regulations
- Flat or pitched roof, with rooflights or a lantern if specified
- Electrics and plumbing by qualified trades, with certificates
- Windows and external doors, including bifolds if chosen
- Building control inspections and completion certificate
Housing across County Durham
Colliery villages across County Durham are lined with brick and stone terraces, many built for mining families. Durham City has Georgian and Victorian streets, Darlington has Victorian terraces and villas, and Peterlee and Newton Aycliffe were planned as post-war new towns. Dales farmhouses in Weardale and Teesdale are stone, often under stone or slate roofs.
Colliery terraces commonly suit loft rooms, rear extensions and window replacement, and many need repointing. New-town homes often benefit from rendering or cladding upgrades and roofline renewal, while stone farmhouses may need lime work.
Winters are cold and the upland dales see snow and strong winds; former coal workings mean ground checks can be needed before building extensions.
Do you need permission in County Durham?
As County Durham is in England, read the following with that system of planning and building control in mind. We check what applies to your house with the council before you receive a quote.
In England, many single-storey rear extensions are permitted development: typically up to 3 m deep on a semi-detached or terraced house and 4 m on a detached house, no more than 4 m high, and covering no more than half the land around the original house. Larger rear extensions can go through the prior approval process. Side extensions, flats, listed buildings, conservation areas and homes where permitted development rights have been removed need planning permission.
Building Regulations approval is needed for almost every extension, covering foundations, structure, insulation, drainage, ventilation and fire safety. If the work is on or near a shared wall or boundary, the Party Wall etc. Act 1996 may apply.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
Free site survey
It starts with a survey at the property, free of charge. We check condition, access and services, ask how you want the finished result to look, and answer any questions you have about a single-storey extension.
Price and scope agreed
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 single-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.
Build and hand over
The job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
What you can expect from us
Frequently asked questions
Do I need planning permission for a single-storey extension?
Whether you need planning permission depends on the extension's size and height, how close it is to boundaries, your home's location, whether it is listed or in a conservation area, and which UK nation you live in. In England, many rear extensions up to 3m deep on a semi or terrace, or 4m on a detached house, can be built under permitted development. We check the rules that apply to your home before quoting.
How much does a single-storey extension cost?
A typical single-storey rear extension of 15–25m² costs £31,500–£68,000, 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.
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 County Durham 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.
Do you cover Darlington, Hartlepool and Stockton-on-Tees?
Yes. As well as County Durham, we cover Darlington, Hartlepool and Stockton-on-Tees and the rest of County Durham. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
Towns in County Durham
Looking for a single-storey extension somewhere in County Durham? Start with the towns below; each links to a page with pricing for your region and coverage details.