Covering Ystalyfera
We work in Ystalyfera (SA9) and the places around it, including Neath, Ammanford and Pontarddulais.
Homes in West Glamorgan
Welsh homes include long terraces built into hillsides, stone cottages and modern estates, and sloping sites often shape how and where an extension can go.
What do you get with a mansard loft conversion?
A mansard loft conversion replaces one or both slopes of a roof with a near-vertical wall, typically at 70 degrees, with small dormer windows set into it. It creates almost a full extra storey and is common on terraced houses in towns and cities, particularly in London.
- Planning and building regulations checks under Welsh rules
- Structural design and party wall process
- Slate cladding and lead-clad dormers
What will a mansard loft conversion cost?
What mansard loft conversions typically cost. These are guide ranges; the written quote for your house replaces them.
| Mansard loft conversions | Guide price incl. VAT |
|---|---|
| Rear mansard | £65,000 to £85,000 |
| Front and rear (double) mansard | £80,000 to £110,000 |
What approvals does a mansard loft conversion need in Wales?
In Wales the planning rules, including what counts as permitted development, are set by the Welsh Government, and Welsh building regulations differ in places from England’s. We check both against your house before drawings are finalised, and handle party wall notices where needed.
This needs full planning permission from your council in Wales.
What can affect a mansard loft conversion?
- A mansard nearly always involves party walls on both sides of a terrace.
- Scaffolding and a temporary roof are usually needed.
What happens after I enquire?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- Construction and completion. One site lead co-ordinates every trade through to the building control certificate.
What people ask before starting
How much does a mansard loft conversion cost?
Typically £65,000 to £110,000 including VAT, depending on whether one or both roof slopes are rebuilt.
Will I need party wall agreements?
Very likely, as the work affects the walls shared with both neighbours on a terrace.
Can you visit a house in Ystalyfera to quote?
Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.
Mansard loft conversions in nearby towns
- Mansard loft conversions in Neath
- Mansard loft conversions in Ammanford
- Mansard loft conversions in Pontarddulais
- Mansard loft conversions in Maesteg
Learn more about mansard loft conversions, or see every project we cover in Ystalyfera.

