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 St Neots?
In St Neots, 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 St Neots 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 |
The biggest cost drivers are:
- Drainage connection distance
- Kitchen and bathroom
- Size and layout
- Heating type
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a garden annexe in St Neots?
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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
Handled as part of most garden annexes:
- Building control sign-off
- Planning drawings and application
- Insulated walls and roof
- Foundations and drainage connections
- Glazed doors and windows
- External cladding or brickwork
How long does it take?
Expect 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 St Neots
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
Projects in St Neots (PE19) are surveyed in person before we quote, so the price reflects your actual property.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 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 St Neots
How much does a garden annexe cost in St Neots?
In St Neots, 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.
Does it need building regulations?
Yes, as it contains sleeping accommodation and services.
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.
Can an annexe be rented out?
Not without further planning permission, as that would make it a separate dwelling.
How long does a garden annexe take in St Neots?
Typically 10 to 16 weeks on site. Design and approvals beforehand usually take 3 to 4 months.