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 Rottingdean?
In Rottingdean, 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. The guide for Rottingdean reflects typical costs in the South East, roughly 12% above the UK-wide figure. 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 |
The biggest cost drivers are:
- Heating type
- Kitchen and bathroom
- Cladding and finishes
- Size and layout
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 Rottingdean?
Here is how the rules work for a garden annexe 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
What we take care of:
- Kitchenette and shower room
- External cladding or brickwork
- Planning drawings and application
- Foundations and drainage connections
- Electrics and heating
- Glazed doors and windows
How long does it take?
The build itself usually takes 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 Rottingdean
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.
If your home is in Rottingdean or close by in Peacehaven, Brighton and Hove, a free home visit is the first step.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about garden annexes in Rottingdean
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.
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 Rottingdean?
In Rottingdean, 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.
Do you build garden annexes in Rottingdean?
Yes. We build garden annexes across Rottingdean, including postcodes BN2 and BN51. Every project starts with a free home visit.
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.