An extension is one of the most effective ways to add living space and value to a London home. If you are thinking about a rear, side return or wrap-around extension, it pays to understand the process first.
Types of Home Extension in London
Rear Extension
The most common type. Single-storey rear extensions up to 4 metres (detached) or 3 metres (semi-detached/terraced) can often be built under Permitted Development.
Side Return Extension
Popular in Victorian and Edwardian properties. Fills the gap between the house and the boundary wall, often combined with a rear extension to create a large open-plan kitchen.
Double Storey Extension
Adds two floors of space for maximum square footage. Usually requires full planning permission and careful architectural design.
Wrap-Around Extension
Combines a rear and a side return extension for the largest possible footprint, and can completely change how the kitchen and living space work.
Home Extension Costs in London
- Single-storey rear extension (3m x 4m): £40,000–£70,000
- Side return extension: £45,000–£75,000
- Double storey extension: £80,000–£150,000+
- Wrap-around extension: £70,000–£120,000
Get Started with Unsel Consultancy
Unsel Consultancy designs extensions and prepares planning applications across London.
Learn more about our council approval drawings or contact us for a free initial consultation.