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 Clwyd?
In Clwyd, a mansard loft conversion typically costs £60,000–£87,500 for a typical rear mansard, including VAT at 20% (standard rate). The guide for Clwyd reflects typical costs in Wales, roughly 8% below the UK-wide figure. 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:
- Roof covering: natural slate costs more
- Bathrooms and finishes
- Number of dormers and lead work
- Scaffolding on busy streets
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a mansard loft conversion in Clwyd?
Before anything is built in Clwyd, we confirm which approvals apply 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.
Our first visit includes a check of your planning history, so you know the route before paying for drawings.
What we handle
On a typical mansard loft conversion we handle:
- New roof structure, slate or tile covering and lead work
- Building control sign-off
- Party wall notices to both neighbours
- Structural design and calculations
- Planning drawings and application
- Staircase and fire-safe escape route
How long does it take?
Allow 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 Clwyd
Wales has many terraced valley streets, stone cottages and post-war estates, so extension designs are shaped by slopes, materials and local character.
Towns we cover in Clwyd include Wrexham, Deeside, Colwyn Bay, Flint, Rhyl and Hawarden.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and fixed quote
Drawings, structural calculations and an itemised, fixed price for the agreed specification.
- 03
Approvals in place
We handle planning, building control and neighbour notices before work starts.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about mansard loft conversions in Clwyd
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.
Do you build mansard loft conversions in Clwyd?
Yes. We build mansard loft conversions across Clwyd, including postcodes CH1, CH4, CH5, CH6 and CH7. Every project starts with a free home visit.
Do I need planning permission for a mansard loft conversion in Clwyd?
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 Clwyd?
In Clwyd, 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.