What is a garden annexe?
A garden annexe is a single-storey building in the garden with its own living space, bathroom and often a kitchenette, used by relatives, older children or guests. Unlike a garden room, it is built as habitable accommodation with foundations, insulation and services.
How much does a garden annexe cost in Accrington?
In Accrington, a garden annexe typically costs £1,700–£2,650 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £59,500–£93,000. Prices across the North West are typically 6% below the UK average for this kind of work, which is reflected in the range for Accrington. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £41,000–£63,500 |
| Typical project (35 m²) | £59,500–£93,000 |
| Larger project (49 m²) | £83,500–£130,000 |
| Rate per m² | £1,700–£2,650 |
The main things that change the cost:
- Access for materials
- Heating type
- Cladding and finishes
- Size and layout
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a garden annexe in Accrington?
Whether you need planning permission depends on your house and its location in England. In England an annexe used as living accommodation usually needs planning permission. Outbuildings built under permitted development must be incidental to the house, such as a gym or office, not a bedroom.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
What we take care of:
- Foundations and drainage connections
- Glazed doors and windows
- Insulated walls and roof
- Electrics and heating
- Kitchenette and shower room
- Planning drawings and application
How long does it take?
Expect 10 to 16 weeks on site. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Accrington
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
Projects in Accrington (BB5) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about garden annexes in Accrington
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
How much does a garden annexe cost in Accrington?
In Accrington, a garden annexe typically costs £1,700–£2,650 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £59,500–£93,000. Your fixed price depends on the survey and drawings.
Will council tax apply?
Annexes can be banded separately, though discounts or exemptions apply in some cases when occupied by family. Check with your council.
Who approves a garden annexe in Accrington?
Planning matters in Accrington go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.