Covering Brentwood
Our coverage around Brentwood (CM14) also includes Billericay (5 miles to the east) and Hornchurch.
Homes in the East of England
The East of England has a large stock of post-war and modern estate housing alongside period homes in market towns, which makes garage conversions, single-storey extensions and loft conversions popular.
What does a garden annexe involve?
A garden annexe is a separate single-storey building in the grounds of a house with its own bedroom, bathroom and kitchenette, used by family members as part of the main household. Unlike a garden office, an annexe that people sleep in normally needs planning permission and full building regulations approval.
- Design and planning application
- Heating, hot water and electrics
- Accessible design options for older relatives
How much should I budget for a garden annexe?
What garden annexes typically cost. These are guide ranges; the written quote for your house replaces them.
| Garden annexes | Guide price incl. VAT |
|---|---|
| Standard specification | £2,400 to £2,900 per m² |
| Good specification | £2,900 to £3,400 per m² |
| High specification | £3,400 to £3,900 per m² |
What approvals does a garden annexe need in England?
Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.
A self-contained annexe used for sleeping and living normally needs planning permission in England.
What should I think about before starting?
- Drainage may need a pump if the garden falls away from the sewer.
- A level threshold and wider doors make the annexe suitable for later life.
From first call to completion
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Questions about a garden annexe in Brentwood
How much does a garden annexe cost?
Around £2,400 to £3,900 per square metre including VAT, depending on finish and services.
How long does an annexe take to build?
About 14 to 24 weeks on site after approvals.
Do you work in Brentwood?
Yes. Brentwood is within our coverage for garden annexes, along with nearby Billericay and Hornchurch.
Garden annexes near Brentwood
- Garden annexes in Billericay
- Garden annexes in Hornchurch
- Garden annexes in Romford
- Garden annexes in Basildon
Learn more about garden annexes, or see every project we cover in Brentwood.

