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 Bexleyheath?
In Bexleyheath, a garden annexe typically costs £2,350–£3,650 per m² of floor area, including VAT at 20% (standard rate). For a typical 35 m² project that is roughly £82,000–£128,000. Prices across London are typically 30% above the UK average for this kind of work, which is reflected in the range for Bexleyheath. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (24 m²) | £56,500–£87,500 |
| Typical project (35 m²) | £82,000–£128,000 |
| Larger project (49 m²) | £115,000–£179,000 |
| Rate per m² | £2,350–£3,650 |
What moves the price most:
- Drainage connection distance
- Heating type
- Cladding and finishes
- Kitchen and bathroom
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 Bexleyheath?
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
- Glazed doors and windows
- Foundations and drainage connections
- External cladding or brickwork
- Building control sign-off
- Planning drawings and application
How long does it take?
Build time is typically 10 to 16 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Bexleyheath
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
We work across Bexleyheath and neighbouring areas such as Welling, Erith and Sidcup. Postcodes we cover in Bexleyheath include DA6 and DA7.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 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 Bexleyheath
How much does a garden annexe cost in Bexleyheath?
In Bexleyheath, a garden annexe typically costs £2,350–£3,650 per m² of floor area, including VAT at 20% (standard rate). A typical 35 m² project comes to roughly £82,000–£128,000. Your fixed price depends on the survey and drawings.
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 it need building regulations?
Yes, as it contains sleeping accommodation and services.
How long does it take?
Typically 10 to 16 weeks on site.
Who approves a garden annexe in Bexleyheath?
Planning matters in Bexleyheath go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.