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.
Whether you live in one of the larger towns, such as Manchester, Oldham, Wigan and Bolton, or somewhere quieter in Greater Manchester, the way we handle a double-storey extension is identical. We survey, agree the specification with you, and confirm a fixed price on paper. Everything is planned under the regulations in force in England, and guide costs in the North West sit at £57,000–£114,000 with VAT.
- Guide price
- £57,000–£114,000 inc VAT
- Time on site
- 14–22 weeks on site
- Planning rules
- England
- Price level
- About 5% below the national guide
- Towns listed
- 42
- Survey
- Free, with a written quote
Double-storey extensions prices in Greater Manchester
Here is how the guide price for a double-storey extension breaks down in Greater Manchester. We start from national figures and adjust for the North West, which comes out about 5% below the national guide. The resulting range, VAT included, is £57,000–£114,000, and a survey, at no cost to you, firms it up.
| Type of job | What it usually involves | Guide in Greater Manchester |
|---|---|---|
| Small (15–20m² total) | A compact rear or side extension adding a small room on each floor. | £38,000–£62,000 |
| Typical (30–40m² total) | A larger kitchen or living room below with a double bedroom or en-suite above. | £57,000–£114,000 |
| Large (50m² plus total) | Wide or deep extensions, often with a new bathroom, steelwork and high-spec glazing. | £95,000–£171,000 |
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 do you get?
- First-floor joists, stud walls and new openings upstairs
- Roof structure tied into the existing roof, tiled to match
- 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
Housing across Greater Manchester
Rows of Victorian red-brick terraces fill much of Manchester, Salford and the mill towns, with stone terraces in the Pennine fringes around Oldham and Saddleworth. South Manchester has Edwardian semis and villas, Wythenshawe was built as a large interwar garden suburb, and city-centre apartments and new estates continue to grow.
Two-up two-down terraces commonly suit loft conversions, kitchen extensions and kitchen refits. Many need repointing and roof work, while semis in the suburbs often take side extensions, driveways and replacement windows.
Rainfall is high, especially near the Pennines, so brickwork, gutters and roof coverings take a steady soaking and freeze-thaw over winter.
Planning and building rules in Greater Manchester
England, Wales, Scotland and Northern Ireland each handle planning a little differently. Greater Manchester comes under England, covered below, and we raise any questions with the council before your quote is finalised.
In England, a two-storey rear extension can only be permitted development if it is no more than 3 m deep, at least 7 m from the rear boundary and finished to match the house. Most double-storey and all two-storey side extensions need full planning permission.
Building Regulations approval is needed, with structural calculations for beams, foundations and the roof. The Party Wall etc. Act 1996 often applies on semi-detached and terraced houses.
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
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.
Written quote
After the survey we send a quote for a double-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.
Booking the work
Preparation matters as much as the build. We agree access, parking and working hours with you, order materials in good time, and confirm any permissions so the job isn't held up once it starts.
Finish and handover
The work is carried out to the agreed specification, with floors and furniture protected and the site kept tidy. At the end we clean up, walk through the finished job with you and hand over any certificates.
What you can expect from us
Frequently asked questions
How long will a double-storey extension take?
On a typical home, allow 14–22 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.
Can the new upstairs room have its own bathroom?
A new upstairs room can usually have an en-suite, provided waste pipes can reach the soil stack or a new one can be installed. Running the waste pipe to the right falls is the main design question, and a pumped system is an option where gravity will not work. We plan bathroom positions at the design stage so pipes, ventilation and insulation are built in rather than added later.
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 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.
Towns in Greater Manchester
Below is our list of Greater Manchester towns for a double-storey extension. If yours isn't shown, we may still cover it, so it is worth asking us directly.
- Altrincham
- Ashton in Makerfield
- Ashton-under-Lyne
- Atherton
- Bolton
- Bury
- Chadderton
- Cheadle Hulme
- Denton
- Droylsden
- Dukinfield
- Eccles
- Failsworth
- Farnworth
- Hazel Grove
- Heywood
- Hindley
- Horwich
- Hyde
- Irlam
- Leigh
- Manchester
- Middleton
- Old Trafford
- Oldham
- Prestwich
- Radcliffe
- Rochdale
- Royton
- Saddleworth
- Sale
- Salford
- Stalybridge
- Stockport
- Stretford
- Swinton
- Tyldesley
- Urmston
- Walkden
- Westhoughton
- Whitefield
- Wigan