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 a side return extension?
A side return extension builds over the narrow passage that runs beside the back of many Victorian and Edwardian terraced houses, widening the kitchen or dining room by a metre or two. It is usually combined with a glazed or part-glazed roof so the deeper room still gets daylight.
- Structural steel to remove the side wall
- Drainage and new gully positions
- Plastering and making good to the old house
How much should I budget for a side return extension?
Typical ranges for side return extensions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| Side return extensions | Guide price incl. VAT |
|---|---|
| Standard specification | £3,350 to £3,700 per m² |
| Good specification | £3,700 to £4,150 per m² |
| High specification | £4,150 to £4,550 per m² |
How is a side return extension approved in Isleworth?
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.
In England a single-storey rear extension can often go ahead under permitted development: up to 3 m deep on an attached house or 4 m on a detached one, no higher than 4 m, with eaves no higher than 3 m within 2 m of a boundary. Deeper extensions, up to 6 m or 8 m, need prior approval from the council first.
What should Isleworth homeowners check first?
- Most side returns touch a shared boundary, so the Party Wall etc. Act 1996 usually applies in England and Wales.
- Many terraces sit in conservation areas, where side extensions need planning permission.
What are the steps?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.
Side return extensions: common questions
Will I need a party wall agreement?
Most likely, because the new wall usually sits on or near the boundary. We serve the notices and work with your neighbour’s surveyor if one is appointed.
How long does a side return take?
About 10 to 14 weeks on site.
How do I get a price for side return 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.
Side return extensions in nearby towns
- Side return extensions in Hounslow
- Side return extensions in Heston
- Side return extensions in Richmond
- Side return extensions in Southall
Learn more about side return extensions, or see every project we cover in Isleworth.