Covering Chelsea
Chelsea sits 2 miles south-west of London, with Battersea 1 miles to the south-east and Fulham 1 miles to the west.
Homes in London
Much of London’s housing is Victorian and Edwardian terraces, which is why side return extensions, rear dormers and mansards are so common. Many streets are in conservation areas, and several boroughs use Article 4 directions that remove some permitted development rights.
What goes into a dormer loft conversion?
Rear dormers on terraced and semi-detached houses are often permitted development in England. We size the dormer to fit the volume allowance, clad it to suit the house (tile-hanging, render, slate or zinc) and fit out the room and en-suite below.
- Dormer frame, roof covering and cladding
- Staircase, insulation and plasterboard
- En-suite, electrics and fire-protected escape route
How much should I budget for a dormer loft conversion?
Typical ranges for dormer loft conversions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.
| Dormer loft conversions | Guide price incl. VAT |
|---|---|
| Rear dormer, bedroom only | £50,000 to £65,000 |
| Full-width dormer with en-suite | £60,000 to £80,000 |
| L-shaped dormer (over rear outrigger) | £65,000 to £90,000 |
How is a dormer loft conversion approved in Chelsea?
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 many loft conversions are permitted development: the extra roof volume must stay within 40 m³ on a terraced house or 50 m³ on a semi or detached house, nothing can sit higher than the existing ridge, no dormer can face a road on the main elevation, and side windows must be obscure-glazed and non-opening below 1.7 m.
What can change the price or programme?
- Dormers on the front of the house facing a road are not permitted development in England.
- A flat dormer roof needs proper falls and a quality membrane.
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.
- 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.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
Dormer loft conversions: common questions
How much does a dormer loft conversion cost?
Typically £50,000 to £80,000 including VAT, and up to around £90,000 for an L-shaped dormer.
Is a dormer permitted development?
Rear dormers in England often are, within the 40 m³ (terrace) or 50 m³ (semi or detached) volume allowance. Front dormers facing a road are not.
Who deals with the council for a project in Chelsea?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Also covering
- Dormer loft conversions in Battersea
- Dormer loft conversions in Fulham
- Dormer loft conversions in Notting Hill
- Dormer loft conversions in Shepherd's Bush
Learn more about dormer loft conversions, or see every project we cover in Chelsea.

