Thornton-Cleveleys annexe extensions, designed and built
From the first sketch to final sign-off, we plan and build annexe extensions in Thornton-Cleveleys and the surrounding Lancashire area.
- Guide price in Thornton-CleveleysFrom £52,000 inc VAT
- PlanningUsually a householder application
- Build time16–24 weeks on site
- Postcode districtsFY2, FY5, FY6

What should I budget for an annexe extension in Thornton-Cleveleys?
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 Thornton-Cleveleys: £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 |
Want a range for your exact size? The guide-price tool takes about a minute.
Extensions in and around Thornton-Cleveleys
We cover Thornton-Cleveleys and the postcode districts FY2, FY5, FY6. We also work in nearby Poulton-le-Fylde (3 miles), Fleetwood (4 miles), Blackpool (4 miles), Lytham St Annes (9 miles).
Just over the Merseyside border, Southport is about 16 miles away. Across the North West, terraced houses with small rear yards suit compact rear and side return extensions, while suburban semis have room for more.
Included in a typical project
- Fire separation and alarms to building regulations
- Planning application describing ancillary use
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Kitchenette, shower room and bedroom finish
- Separate or shared heating and hot water
Accessibility is cheaper to design in than to retrofit. Level access, a 900 mm door width, a level-access shower and space to turn a wheelchair can all be planned into the footprint for little extra cost.
Will the council need to approve it?
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.
Homes in conservation areas, national parks, National Landscapes (formerly AONBs), the Broads and World Heritage Sites have tighter rules, so we always check the property's status and planning history before design starts.
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.
Building over or within 3 m of a public sewer needs the water company's consent, usually through a build-over agreement, before the foundations go in.
Applications are decided by the local planning authority (your district, borough or unitary council).
How the project works
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
We visit your Thornton-Cleveleys home, measure up, talk through what you want and check the planning position.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
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
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Common questions in Thornton-Cleveleys
Do I need building regulations approval in Thornton-Cleveleys?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Will my neighbours in Thornton-Cleveleys 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.
Who do I contract with for an annexe extension in Thornton-Cleveleys?
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 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 Thornton-Cleveleys.
Book a free site visit in Thornton-Cleveleys
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.