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 Shropshire?
In Shropshire, a mansard loft conversion typically costs £63,000–£92,000 for a typical rear mansard, including VAT at 20% (standard rate). Building costs in the West Midlands are close to the UK average, so the figures for Shropshire are close to our national guide. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £63,000–£92,000 |
| Higher specification | £92,000–£115,000 |
The biggest cost drivers are:
- Roof covering: natural slate costs more
- Number of dormers and lead work
- Front, rear or both
- Scaffolding on busy streets
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a mansard loft conversion in Shropshire?
Before anything is built in Shropshire, we confirm which approvals apply 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:
- Staircase and fire-safe escape route
- Structural design and calculations
- Party wall notices to both neighbours
- Dormer windows
- Planning drawings and application
- Insulation, electrics, plumbing and plastering
How long does it take?
Allow 9 to 12 weeks on site, after planning approval. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Shropshire
Across the West Midlands, inter-war and post-war semis make up much of the housing, giving good scope for two-storey side extensions and hip-to-gable lofts.
Towns we cover in Shropshire include Telford, Shrewsbury, Loughton, Wellington and Oswestry.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 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 Shropshire
How much does a mansard loft conversion cost in Shropshire?
In Shropshire, a mansard loft conversion typically costs £63,000–£92,000 for a typical rear mansard, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Can I stay at home?
Usually. The new roof is built under a temporary cover so the house stays dry.
How long does a mansard loft conversion take in Shropshire?
Typically 9 to 12 weeks on site, after planning approval. Design and approvals beforehand usually take 3 to 4 months.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
Does a mansard need planning permission?
Almost always, because it changes the roof shape. Councils assess it against local design guidance.
