Covering Hounslow
Hounslow sits 10 miles west of London, with Isleworth 1 miles to the north-east and Heston 1 miles to the north-west.
Homes in London
Terraced houses dominate many London neighbourhoods, so most projects involve shared walls, narrow access and a party wall process. Conservation areas are widespread, and some boroughs have their own mansard and basement guidance.
What do you get with a garden annexe?
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.
- Foundations and drainage connections
- Heating, hot water and electrics
- Accessible design options for older relatives
What will a garden annexe cost?
Indicative costs for garden annexes. London and the South East usually sit towards the top of each range.
| 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?
English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.
A self-contained annexe used for sleeping and living normally needs planning permission in England.
What should I think about before starting?
- A level threshold and wider doors make the annexe suitable for later life.
- Council tax treatment depends on who lives there; check with your council.
What happens after I enquire?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
Your questions answered
Do I need planning permission for a garden annexe?
Usually yes, because people will sleep in it. Outbuilding permitted development does not cover living accommodation.
How long does an annexe take to build?
About 14 to 24 weeks on site after approvals.
How do I get a price for garden annexes in Hounslow?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Garden annexes in nearby towns
- Garden annexes in Isleworth
- Garden annexes in Heston
- Garden annexes in Richmond
- Garden annexes in Hanworth
Learn more about garden annexes, or see every project we cover in Hounslow.