Covering Wembley
We work in Wembley (HA0) and the places around it, including Brent, Harrow and Greenford.
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 an upward extension?
An upward extension adds a new storey on top of an existing house, most often turning a bungalow into a two-storey or chalet-style home. It can double the floor area without using any of the garden.
- Structural survey of walls and foundations
- Roof removal and temporary weather protection
- Full fit-out of the new rooms
How much should I budget for an upward extension?
Use these ranges to budget for bungalow and upward extensions; the survey turns them into a fixed price for the agreed specification.
| Bungalow and upward extensions | Guide price incl. VAT |
|---|---|
| Chalet conversion with dormers (total) | £45,000 to £85,000 |
| New first floor, standard specification | £2,200 to £2,800 per m² |
| New first floor, good specification | £2,800 to £3,300 per m² |
| New first floor, high specification | £3,300 to £3,800 per m² |
Do you need permission for an upward extension in Wembley?
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.
In England, Class AA permitted development allows an extra storey on many detached and semi-detached houses built between July 1948 and October 2018, subject to a prior approval application covering design, neighbours’ amenity and other matters. Houses in conservation areas and other protected land need full planning permission, as do most chalet conversions with front dormers.
What can affect an upward extension?
- The staircase takes space from the ground floor plan.
- Neighbours’ light and privacy are the main planning tests.
What are the steps?
- 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.
- 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.
Your questions answered
How much does it cost to add a storey?
Around £2,200 to £3,800 per square metre of new floor including VAT, or £45,000 to £85,000 for a chalet conversion with dormers.
How long does it take?
About 12 to 24 weeks on site.
Do you work in Wembley?
Yes. Wembley is within our coverage for bungalow and upward extensions, along with nearby Brent and Harrow.
Bungalow and upward extensions in nearby towns
- Bungalow and upward extensions in Brent
- Bungalow and upward extensions in Harrow
- Bungalow and upward extensions in Greenford
- Bungalow and upward extensions in Willesden
Learn more about bungalow and upward extensions, or see every project we cover in Wembley.

