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.
Getting a single-storey extension right in Birmingham starts with understanding the house you already have: its age, how it was built and what has been altered over the years. We survey first, then commit on paper to a price that holds as long as the scope stays the same. Across the West Midlands, guide prices run at £34,500–£74,000 including VAT, and homes in Aston, Smethwick and Washwood Heath are covered too.
- Guide price
- £34,500–£74,000 inc VAT
- Time on site
- 10–16 weeks on site
- Postcodes
- B1, B2, B3, B4 and B5
- Planning rules
- England
- Local area
- West Midlands
- Survey
- Free, with a written quote
How much does a single-storey extension cost in Birmingham?
The table below shows guide prices for a single-storey extension in Birmingham. They are based on rates in the West Midlands, which run about 2% below the national guide, giving an overall range of £34,500–£74,000. All figures include VAT and are firmed up after a free site survey.
| Type of job | What it usually involves | Guide in Birmingham |
|---|---|---|
| Small extension (8–12m²) | A modest rear or side extension, such as a utility room or a slightly larger kitchen. | £21,500–£39,000 |
| Typical rear extension (15–25m²) | A kitchen-diner or family room with bifold doors and a rooflight or lantern. | £34,500–£74,000 |
| Large or wrap-around (30m² plus) | A wrap-around or wide rear extension, often with structural steelwork into the house. | £69,000–£127,000 |
The main things that change the figure:
- Floor area, shape and number of corners
- Ground conditions, foundation depth and drains to divert
- Steelwork needed to open into the existing house
- Finishes, kitchen, flooring and heating specification
What do you get?
- Groundworks, foundations and below-ground drainage
- Flat or pitched roof, with rooflights or a lantern if specified
- Steel beams to open into the existing house
- Windows and external doors, including bifolds if chosen
- Plastering, screed floor and internal doors
- Building control inspections and completion certificate
Homes in West Midlands
Red-brick Victorian and Edwardian terraces are common in the inner areas of Birmingham, Wolverhampton and the Black Country, ringed by large swathes of 1930s semis with bay windows and hipped roofs. You'll also find post-war council estates, some system-built blocks, Coventry's rebuilt centre and larger detached homes in Solihull and Sutton Coldfield.
An inland climate with regular winter frosts means freeze-thaw damage to soft brick and old mortar is a common reason for repointing and render repairs.
In Birmingham, as elsewhere in West Midlands, we take the building's age and construction into account before recommending anything, because both can change what is involved in a single-storey extension.
Planning and building rules in Birmingham
The notes below cover England, which is where Birmingham sits. Rules change and every property is different, so we speak to the council before pricing your job.
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
Survey and measure
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.
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.
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.
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.
How we work
Frequently asked questions
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.
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.
Do you cover Aston, Smethwick and Washwood Heath?
Yes. As well as Birmingham, we cover Aston, Smethwick and Washwood Heath and the rest of West Midlands. 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.
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.
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.
Near Birmingham
Homes across B1, B2, B3 and B4 in Birmingham are within our coverage, as are those in Aston, Smethwick and Washwood Heath. If you are just outside these areas, ask anyway, because we work right across the UK.