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 Broadstairs?
In Broadstairs, 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. That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. 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 |
Your quote will depend mainly on:
- Size and layout
- Heating type
- Access for materials
- 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 Broadstairs?
Approvals for a garden annexe in Broadstairs follow the rules for 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
From survey to sign-off, the job normally involves:
- Foundations and drainage connections
- Insulated walls and roof
- Glazed doors and windows
- Electrics and heating
- Planning drawings and application
- External cladding or brickwork
How long does it take?
Expect 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 Broadstairs
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.
Broadstairs sits in Kent, about 34 miles east of Southend-on-Sea. We cover the whole of Broadstairs, including postcodes CT10.
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
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about garden annexes in Broadstairs
Can it be accessible?
Yes. Level access, wider doors and a wet room can be designed in.
How long does it take?
Typically 10 to 16 weeks on site.
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 Broadstairs?
In Broadstairs, 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 Broadstairs?
Yes. We build garden annexes across Broadstairs, including postcodes CT10. Every project starts with a free home visit.
