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 Ashton-under-Lyne?
In Ashton-under-Lyne, 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. The guide for Ashton-under-Lyne reflects typical costs in the North West, roughly 6% below the UK-wide figure. 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 biggest cost drivers are:
- Cladding and finishes
- Drainage connection distance
- Size and layout
- Heating type
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a garden annexe in Ashton-under-Lyne?
Approvals for a garden annexe in Ashton-under-Lyne follow the rules for 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
From survey to sign-off, the job normally involves:
- External cladding or brickwork
- Electrics and heating
- Kitchenette and shower room
- Insulated walls and roof
- Building control sign-off
- Glazed doors and windows
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 Ashton-under-Lyne
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
We work across Ashton-under-Lyne and neighbouring areas such as Dukinfield, Stalybridge and Droylsden. Postcodes we cover in Ashton-under-Lyne include OL7.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about garden annexes in Ashton-under-Lyne
How much does a garden annexe cost in Ashton-under-Lyne?
In Ashton-under-Lyne, 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.
How long does a garden annexe take in Ashton-under-Lyne?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.