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.
Whatever type of house you own in Bolton, we start by looking at how a double-storey extension would fit it rather than offering a standard package. We cover BL1, BL2 and BL3 and neighbouring places such as Farnworth, Westhoughton and Radcliffe. One named person looks after you from survey to handover, and nothing is booked until you hold our figure in writing, fixed for the work described.
- Guide price
- £57,000–£114,000 inc VAT
- Time on site
- 14–22 weeks on site
- Postcodes
- BL1, BL2 and BL3
- Planning rules
- England
- Local area
- Greater Manchester
- Survey
- Free, with a written quote
How much does a double-storey extension cost in Bolton?
What should you budget for a double-storey extension in Bolton? Use the figures below as a starting point. Prices in the North West sit about 5% below the national guide, so the range here is £57,000–£114,000 including VAT. Your fixed price comes in writing once we've surveyed the property, at no charge.
| Type of job | What it usually involves | Guide in Bolton |
|---|---|---|
| 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 |
Expect these to shape the final quote:
- Combined floor area across both storeys
- How the new roof joins the existing roof
- Bathrooms, en-suites and plumbing on the upper floor
- Scaffolding duration, access and the level of finishes
What does the job include in Bolton?
- Groundworks, foundations and below-ground drainage
- Insulated cavity walls with brick or render to match the house
- First-floor joists, stud walls and new openings upstairs
- Electrics, plumbing and heating by qualified trades, with certificates
- Windows, external doors, plastering and internal doors
- Building control inspections and completion certificate
Local housing and a double-storey extension
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.
In Bolton, as elsewhere in Greater Manchester, we take the building's age and construction into account before recommending anything, because both can change what is involved in a double-storey extension.
Planning and building rules in Bolton
Homes in Bolton come under the regulations for England, 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 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.
What happens after you get in touch?
A visit to your home
First, someone visits your home in Bolton to see the space, take measurements and note anything that could affect the work, such as access or the condition of what is there. There is no charge for this visit.
Your fixed price
Next you receive a written quote with a fixed price for the agreed specification. It lists what is included, what is not, and how payments are staged, so you can compare it properly.
Dates and permissions
With the quote agreed, we book the work in and handle preparation: permissions where needed, building control notifications, material orders and access arrangements for your Bolton property.
Finish and handover
During the work we protect the areas around it and tidy up at the end of each day. Once complete, we check the finish, remove our materials and hand over paperwork such as building control sign-off where it applies.
Working with SK Home Improvements
Common questions
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.
Is a double-storey extension better value than single-storey?
A double-storey extension usually gives better value per square metre than a single-storey one, because the same foundations and roof serve twice the floor area. The overall cost is higher, and planning can be harder because of the effect on neighbours. If you might want an extra bedroom later, building both floors now avoids a second round of disruption and scaffolding.
Do I need planning permission in Bolton?
It depends on the work, the size of the project, your property type and whether the building is listed or in a conservation area. Bolton is in England, so England's rules apply. Many smaller jobs need no planning application, but some still need building control approval. We check what applies to your address before quoting.
How much will a double-storey extension cost in Bolton?
As a guide, expect to pay £57,000–£114,000 including VAT for a double-storey extension in Bolton. That range is adjusted for the North West, which runs about 5% below the national guide. Where your project lands depends on size, materials, access and the condition of what is already there. We confirm a fixed price in writing after a free survey of your home.
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.
Nearby towns
Whether you're in the centre of Bolton or on its outskirts, BL1, BL2 and BL3 addresses are covered. We extend the same service, and the same fixed-price approach, to Farnworth, Westhoughton and Radcliffe.