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 Coventry?
In Coventry, a mansard loft conversion typically costs £63,000–£92,000 for a typical rear mansard, including VAT at 20% (standard rate). Prices in the West Midlands sit near the national average for this kind of work, and the range for Coventry reflects that. 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 |
What moves the price most:
- Bathrooms and finishes
- Roof covering: natural slate costs more
- Scaffolding on busy streets
- Party wall surveyor fees
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a mansard loft conversion in Coventry?
Here is how the rules work for a mansard loft conversion 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
On a typical mansard loft conversion we handle:
- Dormer windows
- Building control sign-off
- Structural design and calculations
- New roof structure, slate or tile covering and lead work
- Insulation, electrics, plumbing and plastering
- Party wall notices to both neighbours
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 Coventry
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.
Coventry sits in the West Midlands, about 17 miles east of Birmingham. We cover the whole of Coventry, including postcodes CV1.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about mansard loft conversions in Coventry
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
How much does a mansard loft conversion cost in Coventry?
In Coventry, 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.
Who approves a mansard loft conversion in Coventry?
Planning matters in Coventry go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
