Annexe extensions for homes in Merseyside
We design and build annexe extensions for houses in Merseyside, with a written price once the survey and design are done and one point of contact throughout.
- Guide priceFrom £52,000 inc VAT
- PlanningUsually a householder application
- Towns covered17
- Site visitFree, no obligation
Towns in Merseyside
Extensions in and around Merseyside
Towns we cover in Merseyside include Liverpool, Birkenhead, St Helens, Southport, Wallasey, Bootle, Bebington, Huyton. 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.
Annexe extension prices in Merseyside
Labour and material costs vary across the UK, so for Merseyside we use our North West England factor (×0.95). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Merseyside: £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 |
For a figure based on your own dimensions, use our guide-price tool.
What is included
- Planning application describing ancillary use
- Kitchenette, shower room and bedroom finish
- Fire separation and alarms to building regulations
- Design for accessibility: level thresholds, wider doors, walk-in shower
- Separate or shared heating and hot water
Planning rules that apply in Merseyside
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.
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 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
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We draw the design, agree it with you and handle planning or permitted development checks and building regulations.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
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 Merseyside?
On site, typically 16 to 24 weeks once approvals are in place. Before that, allow 10–16 weeks design and approvals.
Do I need building regulations approval in Merseyside?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Merseyside, 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.
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 Merseyside.
Book a free site visit in Merseyside
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.