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 Exmouth?
In Exmouth, a garden annexe typically costs £1,850–£2,850 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £65,000–£100,000. Prices in the South West sit near the national average for this kind of work, and the range for Exmouth reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £44,500–£68,500 |
| Typical project (35 m²) | £65,000–£100,000 |
| Larger project (49 m²) | £90,500–£139,500 |
| Rate per m² | £1,850–£2,850 |
What moves the price most:
- Heating type
- Access for materials
- Cladding and finishes
- Drainage connection distance
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 Exmouth?
Before anything is built in Exmouth, we confirm which approvals apply 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
What we take care of:
- Electrics and heating
- External cladding or brickwork
- Glazed doors and windows
- Insulated walls and roof
- Kitchenette and shower room
- Building control sign-off
How long does it take?
Expect 10 to 16 weeks on site. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Exmouth
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
We work across Exmouth and neighbouring areas such as Heavitree, Exeter and Newton Abbot. Postcodes we cover in Exmouth include EX8.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and 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 Exmouth
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 it take?
Typically 10 to 16 weeks on site.
Who approves a garden annexe in Exmouth?
Planning matters in Exmouth go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How much does a garden annexe cost in Exmouth?
In Exmouth, a garden annexe typically costs £1,850–£2,850 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £65,000–£100,000. Your fixed price depends on the survey and drawings.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
