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 Esher?
In Esher, 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 Esher 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 |
What moves the price most:
- Heating type
- Drainage connection distance
- Kitchen and bathroom
- Size and layout
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 Esher?
Approvals for a garden annexe in Esher 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.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
From survey to sign-off, the job normally involves:
- Insulated walls and roof
- Planning drawings and application
- Electrics and heating
- External cladding or brickwork
- Kitchenette and shower room
- Building control sign-off
How long does it take?
Build time is typically 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 Esher
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.
Esher sits in Surrey, about 13 miles north-east of Guildford. We cover the whole of Esher, including postcodes KT10.
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 fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 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 Esher
How long does a garden annexe take in Esher?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
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.
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.
How much does a garden annexe cost in Esher?
In Esher, 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.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
