What is a mansard loft conversion?
A mansard loft conversion rebuilds the roof with a nearly vertical slope (about 72 degrees) and a flat top, effectively adding a new storey. Small dormer windows sit within the steep slope. Mansards are common on period terraces in towns and cities.
How much does a mansard loft conversion cost in Melksham?
In Melksham, a mansard loft conversion typically costs £66,500–£97,000 for a typical rear mansard, including VAT at 20% (standard rate). Building costs in the South West are close to the UK average, so the figures for Melksham are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £66,500–£97,000 |
| Higher specification | £97,000–£121,000 |
The main things that change the cost:
- Front, rear or both
- Party wall surveyor fees
- Scaffolding on busy streets
- Bathrooms and finishes
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a mansard loft conversion in Melksham?
The approval route for Melksham is set by planning law in England. In England a mansard almost always needs planning permission because it changes the roof shape. Many councils publish design guidance for mansards on terraced streets, and some streets are more likely to be approved where neighbours already have one.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Party wall notices to both neighbours
- New roof structure, slate or tile covering and lead work
- Staircase and fire-safe escape route
- Building control sign-off
- Structural design and calculations
- Dormer windows
How long does it take?
Build time is typically 9 to 12 weeks on site, after planning approval. Design and approvals come first and typically take 3 to 4 months, depending on the approval route.
Building in Melksham
The South West mixes stone and render cottages with post-war and newer estates, and local materials matter more here when matching an extension.
We work across Melksham and neighbouring areas such as Trowbridge, Chippenham and Bath. Postcodes we cover in Melksham include SN12.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about mansard loft conversions in Melksham
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
Can I stay at home?
Usually. The new roof is built under a temporary cover so the house stays dry.
How much does a mansard loft conversion cost in Melksham?
In Melksham, a mansard loft conversion typically costs £66,500–£97,000 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
How long does a mansard loft conversion take in Melksham?
Typically 9 to 12 weeks on site, after planning approval. Design and approvals beforehand usually take 3 to 4 months.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.