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 Caldicot?
In Caldicot, 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 Caldicot 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 |
What moves the price most:
- Bathrooms and finishes
- Scaffolding on busy streets
- Front, rear or both
- Party wall surveyor fees
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 Caldicot?
Here is how the rules work for a mansard loft conversion in Wales. In Wales a mansard roof needs planning permission and is judged against local design guidance.
The Party Wall etc. Act 1996 applies in Wales, so notices must be served before work on a shared wall, on the boundary, or excavation close to a neighbour’s foundations.
We check this for your address before design work starts, so there are no surprises later.
What we handle
On a typical mansard loft conversion we handle:
- New roof structure, slate or tile covering and lead work
- Planning drawings and application
- Insulation, electrics, plumbing and plastering
- Building control sign-off
- Dormer windows
- Structural design and calculations
How long does it take?
Build time is typically 9 to 12 weeks on site, after planning approval. Before that, surveys, drawings and approvals usually take 3 to 4 months, longer if the council asks for changes.
Building in Caldicot
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
Caldicot sits in Gwent, about 10 miles east of Newport. We cover the whole of Caldicot, including postcodes NP26.
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
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 Caldicot
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
Do I need planning permission for a mansard loft conversion in Caldicot?
In Wales a mansard roof needs planning permission and is judged against local design guidance.
How long does it take?
Around 9 to 12 weeks on site, plus 2 to 3 months for planning and party wall matters beforehand.
How much does a mansard loft conversion cost in Caldicot?
In Caldicot, 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.
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
Do you build mansard loft conversions in Caldicot?
Yes. We build mansard loft conversions across Caldicot, including postcodes NP26. Every project starts with a free home visit.