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 Sittingbourne?
In Sittingbourne, a garden annexe typically costs £2,000–£3,150 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £70,000–£110,000. Prices across the South East are typically 12% above the UK average for this kind of work, which is reflected in the range for Sittingbourne. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £48,000–£75,500 |
| Typical project (35 m²) | £70,000–£110,000 |
| Larger project (49 m²) | £98,000–£154,500 |
| Rate per m² | £2,000–£3,150 |
Your quote will depend mainly on:
- Drainage connection distance
- Access for materials
- Kitchen and bathroom
- Size and layout
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a garden annexe in Sittingbourne?
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
The work we manage on a garden annexe:
- Electrics and heating
- Planning drawings and application
- Building control sign-off
- Insulated walls and roof
- Foundations and drainage connections
- Kitchenette and shower room
How long does it take?
Allow 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 Sittingbourne
The South East has a broad mix of housing, from Victorian terraces in the towns to post-war semis and newer estates, so extension types vary street by street.
Our Sittingbourne coverage includes postcode districts ME10, and we also work in nearby places such as Faversham, Gillingham and Chatham.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about garden annexes in Sittingbourne
Can it be accessible?
Yes. Level access, wider doors and a wet room can be designed in.
Does a garden annexe need planning permission?
Usually yes if it is used as living accommodation. Outbuildings under permitted development must be incidental to the house, such as a gym or office, not bedrooms.
How much does a garden annexe cost in Sittingbourne?
In Sittingbourne, a garden annexe typically costs £2,000–£3,150 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £70,000–£110,000. Your fixed price depends on the survey and drawings.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
How long does a garden annexe take in Sittingbourne?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.