Covering Corsham
Alongside Corsham, we also cover Chippenham, Calne (8 miles to the east) and Trowbridge.
Homes in the South West
Homes in the South West range from coastal and rural properties in stone and slate to city terraces and modern estates, so extensions are designed to match the local materials.
What do you get with a mansard loft conversion?
A mansard loft conversion replaces one or both slopes of a roof with a near-vertical wall, typically at 70 degrees, with small dormer windows set into it. It creates almost a full extra storey and is common on terraced houses in towns and cities, particularly in London.
- Structural design and party wall process
- Slate cladding and lead-clad dormers
- Staircase, insulation and fit-out
What is the guide price for a mansard loft conversion in Corsham?
What mansard loft conversions typically cost. These are guide ranges; the written quote for your house replaces them.
| Mansard loft conversions | Guide price incl. VAT |
|---|---|
| Rear mansard | £65,000 to £85,000 |
| Front and rear (double) mansard | £80,000 to £110,000 |
Planning and building rules in Corsham
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. Many councils publish guidance on mansard design.
What can change the price or programme?
- A mansard nearly always involves party walls on both sides of a terrace.
- Scaffolding and a temporary roof are usually needed.
What happens after I enquire?
- 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.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
What people ask before starting
Does a mansard need planning permission?
Almost always, because it changes the roof profile.
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 Corsham?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Other towns nearby
- Mansard loft conversions in Chippenham
- Mansard loft conversions in Calne
- Mansard loft conversions in Trowbridge
- Mansard loft conversions in Bath
Learn more about mansard loft conversions, or see every project we cover in Corsham.

