Colne annexe extensions, designed and built
Colne homeowners can use us for the whole annexe extension project: survey, design, planning or permitted development checks, building regulations and the build itself.
- Guide price in ColneFrom £52,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsBB8

Planning and approvals in Colne
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
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).
What we take care of
- Kitchenette, shower room and bedroom finish
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Separate or shared heating and hot water
- Fire separation and alarms to building regulations
Local to Colne
Site visits are available across Colne (BB8). Nearby, we also take on projects in Nelson (2 miles), Burnley (5 miles), Accrington (11 miles), Rawtenstall (12 miles).
Across the North West, terraced houses with small rear yards suit compact rear and side return extensions, while suburban semis have room for more.
Guide prices for Colne
Labour and material costs vary across the UK, so for Colne we use our North West England factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Colne: £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.
From first visit to completion
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
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Annexe extension questions answered
How long does an annexe extension take to build in Colne?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Who do I contract with for an annexe extension in Colne?
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.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Colne, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
Does an annexe extension need planning permission?
Usually yes, because of its size and the way it will be used. Councils check that it stays ancillary to the main house, so the application must describe the use clearly.
Will an annexe affect council tax?
It can. Some annexes are assessed separately for council tax, with discounts or exemptions in some cases when occupied by a relative. Check with the Valuation Office Agency (England and Wales), your local assessor (Scotland) or Land & Property Services (Northern Ireland).
Book a free site visit in Colne
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.