What is a rooflight loft conversion?

A rooflight loft conversion (sometimes called a roof window conversion) keeps the existing roof shape and adds roof windows that sit flush with the slope. The floor is strengthened, a staircase is added and the space is insulated and finished.
How much does a rooflight loft conversion cost in Clwyd?
In Clwyd, a rooflight loft conversion typically costs £27,500–£41,500 for a typical rooflight conversion, 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 Clwyd. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £27,500–£41,500 |
| Higher specification | £41,500–£52,000 |
What moves the price most:
- Number of roof windows
- Staircase position
- Fire safety upgrades
- Floor and roof strengthening
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 rooflight loft conversion in Clwyd?
Approvals for a rooflight loft conversion in Clwyd follow the rules for Wales. In Wales roof windows that sit close to the roof slope are generally permitted development outside protected areas.
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:
- Drawings and structural calculations
- Insulation between and under rafters
- Building control sign-off
- Floor joists and any steel beams
- Staircase and fire-safe escape route
- Electrics, heating and plastering
How long does it take?
Build time is typically 4 to 6 weeks on site. Before that, surveys, drawings and approvals usually take 6 to 12 weeks, longer if the council asks for changes.
Building in Clwyd
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
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 sign-off
We run the build to a written programme and hand over the completion certificate.
Questions about rooflight loft conversions in Clwyd
How long does a rooflight loft conversion take in Clwyd?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
Do I need planning permission for a rooflight loft conversion in Clwyd?
In Wales roof windows that sit close to the roof slope are generally permitted development outside protected areas.
How much head height do I need?
Around 2.2 metres or more from the top of the ceiling joists to the ridge is a good starting point. Insulation and new floor joists reduce the height.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
How much does a rooflight loft conversion cost in Clwyd?
In Clwyd, a rooflight loft conversion typically costs £27,500–£41,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
