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 Heavitree?
In Heavitree, 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. Building costs in the South West are close to the UK average, so the figures for Heavitree are close to our national guide. 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
- Size and layout
- Cladding and finishes
- Kitchen and bathroom
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a garden annexe in Heavitree?
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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
On a typical garden annexe we handle:
- Building control sign-off
- Glazed doors and windows
- Planning drawings and application
- Kitchenette and shower room
- External cladding or brickwork
- Foundations and drainage connections
How long does it take?
Expect 10 to 16 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Heavitree
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
Heavitree sits in Devon. We cover the whole of Heavitree, including postcodes EX2 and EX4.
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 in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about garden annexes in Heavitree
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.
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.
How much does a garden annexe cost in Heavitree?
In Heavitree, 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.
Can it be accessible?
Yes. Level access, wider doors and a wet room can be designed in.
How long does a garden annexe take in Heavitree?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.