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 Bowthorpe?
In Bowthorpe, a garden annexe typically costs £1,900–£2,950 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £66,500–£103,000. Building costs in the East of England run about 6% above the UK average, and the figures for Bowthorpe are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £45,500–£71,000 |
| Typical project (35 m²) | £66,500–£103,000 |
| Larger project (49 m²) | £93,000–£144,500 |
| Rate per m² | £1,900–£2,950 |
Your quote will depend mainly on:
- Access for materials
- Heating type
- Drainage connection distance
- 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 Bowthorpe?
Before anything is built in Bowthorpe, 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
Handled as part of most garden annexes:
- Electrics and heating
- Insulated walls and roof
- Glazed doors and windows
- Building control sign-off
- External cladding or brickwork
- Planning drawings and application
How long does it take?
Allow 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 Bowthorpe
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
Bowthorpe sits in Norfolk, about 3 miles west of Norwich. We cover the whole of Bowthorpe, including postcodes NR5.
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 Bowthorpe
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
How much does a garden annexe cost in Bowthorpe?
In Bowthorpe, a garden annexe typically costs £1,900–£2,950 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £66,500–£103,000. Your fixed price depends on the survey and drawings.
Who approves a garden annexe in Bowthorpe?
Planning matters in Bowthorpe go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
Can it be accessible?
Yes. Level access, wider doors and a wet room can be designed in.