Covering Beaconsfield
Our coverage around Beaconsfield (HP9) also includes Amersham, High Wycombe and Maidenhead.
Homes in the South East
Housing across the South East mixes inter-war semis, post-war estates and older cottages in villages and market towns, so rear and side extensions, hip-to-gable lofts and garage conversions all come up regularly.
What do you get with 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.
- Volume calculation and permitted development check
- Lawful development certificate or planning drawings
- Dormer frame, roof covering and cladding
What will a dormer loft conversion cost?
Use these ranges to budget for dormer loft conversions; the survey turns them into a fixed price for the agreed specification.
| 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 |
What approvals does a dormer loft conversion need in England?
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 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. Houses in conservation areas, National Parks and National Landscapes cannot use these roof-extension rights, so dormers there need planning permission (a rooflight-only conversion can still be permitted development), and flats always need permission.
What should I think about before starting?
- Dormer cheeks close to a shared wall can trigger the Party Wall Act.
- L-shaped dormers are common on Victorian terraces with a rear outrigger.
From first call to completion
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- 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.
Your questions answered
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.
What cladding can a dormer have?
Tile-hanging to match the roof, render, slate, timber or zinc, depending on the house and any planning conditions.
How do I get a price for dormer loft conversions in Beaconsfield?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Dormer loft conversions near Beaconsfield
- Dormer loft conversions in Amersham
- Dormer loft conversions in High Wycombe
- Dormer loft conversions in Maidenhead
- Dormer loft conversions in Slough
Learn more about dormer loft conversions, or see every project we cover in Beaconsfield.

