Annexe extensions in Farnworth
From the first sketch to final sign-off, we plan and build annexe extensions in Farnworth and the surrounding Greater Manchester area.
- Guide price in FarnworthFrom £52,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsBL3, BL4, M38
What should I budget for an annexe extension in Farnworth?
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 Farnworth: £1,900 to £3,610 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| Studio annexe 25 m² | £52,000 – £65,500 | £57,000 – £71,500 | £71,000 – £90,500 |
| One-bedroom annexe 35 m² | £66,500 – £83,500 | £79,500 – £100,000 | £99,500 – £126,500 |
| Larger annexe 45 m² | £85,500 – £107,000 | £102,500 – £128,500 | £128,000 – £162,500 |
Try the guide-price tool to see a range for your own size and finish.
Planning and approvals in Farnworth
In England an annexe that stays part of the household and connects to the house is assessed as an extension, but its size usually takes it beyond permitted development, so a householder application describing the ancillary use is the normal route.
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.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Is an annexe extension right for your house?
- Multi-generational families
- Relatives who need support close by
- Homes with a large side or rear garden
Working in Farnworth
Across BL3, BL4, M38, we can visit, measure and advise. We also work in nearby Walkden (2 miles), Bolton (3 miles), Radcliffe (3 miles), Tyldesley (4 miles).
For homes towards Merseyside, Golborne is around 10 miles away. 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.
What happens next
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
First, a site visit: we look at the house, garden, access and drains and listen to what you need.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
The build is managed from start to finish, inspected at each stage and signed off on completion.
Common questions in Farnworth
Do you cover all of Farnworth?
Yes. We cover Farnworth and the surrounding parts of Greater Manchester. Site visits are free and there is no obligation.
Who do I contract with for an annexe extension in Farnworth?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Will my neighbours in Farnworth be involved?
If a planning application or prior approval is needed, the council notifies neighbours. If the work is on or near a shared boundary, party wall notices may also be needed.
Can the annexe have its own front door?
Yes, many do, but it should still connect to the main house to stay clearly part of it.
How much does an annexe extension cost?
Our guide range is about £1,900 to £3,610 per m² including VAT. A one-bedroom annexe of about 35 m² is typically £79,500 to £100,000 at standard spec in Farnworth.
Book a free site visit in Farnworth
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.