Covering Gwynedd and Anglesey
Our mansard loft conversions service in Gwynedd and Anglesey covers Bangor, Holyhead, Caernarfon and Llangefni and more.
Homes in Gwynedd and Anglesey
Housing in Wales ranges from terraced streets in the valleys and older industrial towns to stone-built homes in rural areas and modern estates around the cities.
What is 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.
- Structural design and party wall process
- Slate cladding and lead-clad dormers
- Staircase, insulation and fit-out
What will a mansard loft conversion cost?
Use these ranges to budget for mansard loft conversions; the survey turns them into a fixed price for the agreed specification.
| Mansard loft conversions | Guide price incl. VAT |
|---|---|
| Rear mansard | £65,000 to £85,000 |
| Front and rear (double) mansard | £80,000 to £110,000 |
Do you need permission for a mansard loft conversion in Gwynedd and Anglesey?
Planning decisions in Wales are made by the local council, using permitted development rules set by the Welsh Government rather than England’s. Building regulations in Wales have their own approved documents, and the Party Wall etc. Act 1996 applies to work on shared walls and boundaries.
This needs full planning permission from your council in Wales.
What should I think about before starting?
- A mansard nearly always involves party walls on both sides of a terrace.
- Council design guides often require natural slate and lead.
What happens after I enquire?
- Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
- We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
- Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
What people ask before starting
How long does a mansard take?
Around 10 to 14 weeks on site after planning approval.
Will I need party wall agreements?
Very likely, as the work affects the walls shared with both neighbours on a terrace.
Who deals with the council for a project in Gwynedd and Anglesey?
We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.
Mansard loft conversions in nearby towns
- Mansard loft conversions in Bangor
- Mansard loft conversions in Holyhead
- Mansard loft conversions in Caernarfon
- Mansard loft conversions in Llangefni
- Mansard loft conversions in Pwllheli
Learn more about mansard loft conversions, or see every project we cover in Gwynedd and Anglesey.