Covering Isleworth
Our coverage around Isleworth (TW7) also includes Hounslow (1 miles to the south-west) and Heston.
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 is included in a double-storey extension in Isleworth?
A double-storey extension adds new rooms on both the ground and first floor in one build, typically a larger kitchen or living space downstairs and an extra bedroom or bathroom above. Because the roof and foundations are shared, the cost per square metre is usually lower than a single-storey extension.
- Measured survey, design and planning drawings
- Foundations, steelwork, brick and block walls, roof
- Windows, insulation, plastering, electrics and plumbing
What is the guide price for a double-storey extension in Isleworth?
Guide prices for double-storey extensions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.
| Double-storey extensions | 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 £3,850 per m² |
Planning and building rules 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.
Two-storey rear extensions can sometimes be permitted development in England (no more than 3 m deep, at least 7 m from the rear boundary, roof pitch to match), but most two-storey and all two-storey side extensions need householder planning permission.
What should Isleworth homeowners check first?
- The new roof is tied into the old one, so roof tiles and ridge details need to match.
- The first-floor link can mean moving a bathroom or reshaping the landing.
From first call to completion
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- 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.
- Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.
Double-storey extensions: common questions
Does a two-storey extension need planning permission?
Usually yes. In England some two-storey rear extensions are permitted development, but side extensions over one storey always need planning permission.
Will we need to move out?
Most people stay. The noisiest stage is when we break through into the existing first floor, which we plan for a short window.
How do I get a price for double-storey extensions in Isleworth?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Other towns nearby
- Double-storey extensions in Hounslow
- Double-storey extensions in Heston
- Double-storey extensions in Richmond
- Double-storey extensions in Southall
Learn more about double-storey extensions, or see every project we cover in Isleworth.