Covering Windsor
Windsor sits 16 miles east of Reading, with Slough 2 miles to the north and Egham 4 miles to the south-east.
Homes in the South East
Housing across the South East mixes inter-war semis, post-war estates and older cottages in villages and market towns, so rear and side extensions, hip-to-gable lofts and garage conversions all come up regularly.
What is included in a garden annexe in Windsor?
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.
- Brick, block or timber-frame structure
- Kitchenette and shower room
- Heating, hot water and electrics
What is the guide price for a garden annexe in Windsor?
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 |
How is a garden annexe approved in Windsor?
In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.
A self-contained annexe used for sleeping and living normally needs planning permission in England. Permitted development for outbuildings does not cover living accommodation.
What can affect a garden annexe?
- The annexe normally has to remain part of the main household, not let as a separate home.
- Council tax treatment depends on who lives there; check with your council.
From first call to completion
- 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.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Garden annexes: common questions
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.
Can I rent the annexe out?
Usually not without a separate planning permission, because councils normally require it to stay part of the main house.
How do I get a price for garden annexes in Windsor?
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 Slough
- Garden annexes in Egham
- Garden annexes in Staines
- Garden annexes in Maidenhead
Learn more about garden annexes, or see every project we cover in Windsor.

