Covering Isleworth
Alongside Isleworth, we also cover Hounslow, Heston (2 miles to the west) and Richmond.
Homes in London
London projects often mean working on period terraces with neighbours on both sides, tight access through the house and conservation area controls, so careful planning and party wall work matter as much as the build.
What is 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.
- Design and planning application
- Brick, block or timber-frame structure
- Kitchenette and shower room
What is the guide price for a garden annexe in Isleworth?
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 |
Do you need permission for a garden annexe in Isleworth?
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.
What should I think about before starting?
- Drainage may need a pump if the garden falls away from the sewer.
- Council tax treatment depends on who lives there; check with your council.
How does the project run?
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
Garden annexes: common questions
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.
Who deals with the council for a project in Isleworth?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Also covering
- Garden annexes in Hounslow
- Garden annexes in Heston
- Garden annexes in Richmond
- Garden annexes in Southall
Learn more about garden annexes, or see every project we cover in Isleworth.