Covering Brentwood
Brentwood sits 11 miles south-west of Chelmsford, with Billericay 5 miles to the east and Hornchurch 6 miles to the south-west.
Homes in the East of England
Across the East of England, newer estates often have integral garages and room for rear extensions, while older towns have Victorian terraces and conservation areas that shape what can be built.
What is included in a mansard loft conversion in Brentwood?
Mansards are a bigger structural job than other conversions because the roof is largely rebuilt. They normally need planning permission, and many councils have design guides setting the angle, materials and window style. We prepare the design to those guides and build in slate, lead and timber or approved alternatives.
- Planning application to local design guidance
- Roof removal and new mansard frame
- En-suite, electrics and fire safety
How much does a mansard loft conversion cost in Brentwood?
Indicative costs for mansard loft conversions. London and the South East usually sit towards the top of each range.
| Mansard loft conversions | Guide price incl. VAT |
|---|---|
| Rear mansard | £65,000 to £85,000 |
| Front and rear (double) mansard | £80,000 to £110,000 |
Do you need permission for a mansard loft conversion in Brentwood?
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.
Mansard conversions change the shape of the roof significantly, so they usually need planning permission in England.
What should I think about before starting?
- The roof is open for longer than with a dormer, so weather protection matters.
- Scaffolding and a temporary roof are usually needed.
What are the steps?
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- 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.
What people ask before starting
How long does a mansard take?
Around 10 to 14 weeks on site after planning approval.
Will I need party wall agreements?
Very likely, as the work affects the walls shared with both neighbours on a terrace.
How do I get a price for mansard loft conversions in Brentwood?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Mansard loft conversions near Brentwood
- Mansard loft conversions in Billericay
- Mansard loft conversions in Hornchurch
- Mansard loft conversions in Romford
- Mansard loft conversions in Basildon
Learn more about mansard loft conversions, or see every project we cover in Brentwood.

