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 Hawarden?
In Hawarden, a mansard loft conversion typically costs £60,000–£87,500 for a typical rear mansard, including VAT at 20% (standard rate). Building costs in Wales run about 8% below the UK average, and the figures for Hawarden are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rear mansard | £60,000–£87,500 |
| Higher specification | £87,500–£109,500 |
The main things that change the cost:
- Roof covering: natural slate costs more
- Bathrooms and finishes
- Party wall surveyor fees
- 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 Hawarden?
The approval route for Hawarden is set by planning law in Wales. In Wales a mansard roof needs planning permission and is judged against local design guidance.
Building regulations in Wales are set by the Welsh Government. Approval comes from the council’s building control service or a registered building control approver, with inspections during the work and a completion certificate 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
On a typical mansard loft conversion we handle:
- Party wall notices to both neighbours
- Insulation, electrics, plumbing and plastering
- Structural design and calculations
- Staircase and fire-safe escape route
- New roof structure, slate or tile covering and lead work
- Dormer windows
How long does it take?
The build itself usually takes 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 Hawarden
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
Our Hawarden coverage includes postcode districts CH5, and we also work in nearby places such as Deeside, Buckley and Flint.
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 fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about mansard loft conversions in Hawarden
How much does a mansard loft conversion cost in Hawarden?
In Hawarden, a mansard loft conversion typically costs £60,000–£87,500 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 Hawarden?
Planning matters in Hawarden go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Do I need planning permission for a mansard loft conversion in Hawarden?
In Wales a mansard roof needs planning permission and is judged against local design guidance.
Why choose a mansard over a dormer?
A mansard gives more usable floor space and a neater appearance from the street, but costs more and needs planning permission.
Can I stay at home?
Usually. The new roof is built under a temporary cover so the house stays dry.
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.
