Double-storey extensions across Bolton
We design and build double-storey extensions for houses in Bolton, with a written price once the survey and design are done and one point of contact throughout.
- Guide price in BoltonFrom £36,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsBL1, BL2, BL3, BL4, BL7
What we take care of
- Building regulations drawings and structural design
- Foundations sized for two floors
- Ground and first floor structure, roof tied into the existing roof
- Breaking through at both levels, stairs and landing changes where needed
What should I budget for a double-storey extension in Bolton?
These guide figures apply our North West England adjustment (×0.95) to national rates. They include VAT at 20% and cover the build itself; design and council fees are listed separately.
Typical rates in Bolton: £1,470 to £2,850 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 3 m × 4 m, two floors 24 m² | £36,000 – £43,500 | £41,000 – £54,000 | £52,000 – £68,500 |
| 4 m × 4 m, two floors 32 m² | £47,000 – £56,500 | £54,500 – £71,500 | £69,500 – £91,500 |
| 4 m × 6 m, two floors 48 m² | £70,500 – £84,500 | £82,000 – £107,500 | £104,500 – £137,000 |
Try the guide-price tool to see a range for your own size and finish.
Planning rules that apply in Bolton
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Covering Bolton
We cover Bolton and the postcode districts BL1, BL2, BL3, BL4, BL7, M38. The same team covers Farnworth (3 miles), Westhoughton (4 miles), Radcliffe (5 miles), Atherton (5 miles), all within easy reach.
The North West has a high share of Victorian and Edwardian terraces with rear yards and outriggers, plus large areas of inter-war semis in the suburbs.
Our process, step by step
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
A designer visits, takes measurements and photos, and discusses layouts, budget and timing with you.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
You receive a written, itemised price and programme. Nothing starts until you are happy with it.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Your questions about a double-storey extension in Bolton
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Bolton, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a double-storey extension take to build in Bolton?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 8–16 weeks design and approvals.
Do I need building regulations approval in Bolton?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Does a double-storey extension need planning permission?
Often, yes. In England a two-storey rear extension can be permitted development only if it projects no more than 3 m and sits at least 7 m from the rear boundary, with matching roof pitch and obscure side windows. Side extensions over one storey always need planning permission. We confirm the route at the survey.
Do I need a Party Wall Agreement?
If you are in England or Wales and the work involves a shared wall or digging foundations close to a neighbour, the Party Wall etc. Act 1996 applies and notices must be served before work starts. We tell you which notices are needed.
Book a free site visit in Bolton
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.