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 Brecon?
In Brecon, a mansard loft conversion typically costs £60,000–£87,500 for a typical rear mansard, including VAT at 20% (standard rate). Prices across Wales are typically 8% below the UK average for this kind of work, which is reflected in the range for Brecon. 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 |
Your quote will depend mainly on:
- Roof covering: natural slate costs more
- Bathrooms and finishes
- Number of dormers and lead work
- Party wall surveyor fees
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 Brecon?
The approval route for Brecon 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.
We check this for your address before design work starts, so there are no surprises later.
What we handle
What we take care of:
- Planning drawings and application
- New roof structure, slate or tile covering and lead work
- Dormer windows
- Staircase and fire-safe escape route
- Building control sign-off
- 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 Brecon
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
If your home is in Brecon or close by in Merthyr Tydfil, Ebbw Vale and Aberdare, a free home visit is the first step.
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
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about mansard loft conversions in Brecon
Do I need party wall agreements?
Yes, mansards on terraced houses almost always involve both party walls.
What roof covering is used?
Natural slate is traditional; some councils accept other materials. We follow local guidance.
Who approves a mansard loft conversion in Brecon?
Planning matters in Brecon 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.
How much does a mansard loft conversion cost in Brecon?
In Brecon, 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 planning permission for a mansard loft conversion in Brecon?
In Wales a mansard roof needs planning permission and is judged against local design guidance.