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 Merthyr Tydfil?
In Merthyr Tydfil, a rooflight loft conversion typically costs £27,500–£41,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Building costs in Wales run about 8% below the UK average, and the figures for Merthyr Tydfil are adjusted to reflect that. 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 |
The main things that change the cost:
- Fire safety upgrades
- Bathroom or not
- Staircase position
- Number of roof windows
For a figure based on your own measurements, try the guide price tool, then book a free home visit for a fixed quote.
Do you need planning permission for a rooflight loft conversion in Merthyr Tydfil?
Whether you need planning permission depends on your house and its location in Wales. In Wales roof windows that sit close to the roof slope are generally permitted development outside protected areas.
The Party Wall etc. Act 1996 applies in Wales, so notices must be served before work on a shared wall, on the boundary, or excavation close to a neighbour’s foundations.
At the survey we check your house’s planning history and any restrictions, and tell you which route applies.
What we handle
Handled as part of most rooflight loft conversions:
- Floor joists and any steel beams
- Roof windows installed
- Building control sign-off
- Electrics, heating and plastering
- Head-height survey
- Staircase and fire-safe escape route
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 Merthyr Tydfil
Terraced houses in Welsh towns often have narrow plots, which suits rear and side return extensions and rear dormers.
We work across Merthyr Tydfil and neighbouring areas such as Aberdare, Rhondda and Ebbw Vale. Postcodes we cover in Merthyr Tydfil include CF47.
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
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about rooflight loft conversions in Merthyr Tydfil
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
How much does a rooflight loft conversion cost in Merthyr Tydfil?
In Merthyr Tydfil, 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.
How long does a rooflight loft conversion take in Merthyr Tydfil?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
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.
Do I need planning permission for a rooflight loft conversion in Merthyr Tydfil?
In Wales roof windows that sit close to the roof slope are generally permitted development outside protected areas.