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 Merseyside?
In Merseyside, a rooflight loft conversion typically costs £28,000–£42,500 for a typical rooflight conversion, including VAT at 20% (standard rate). The guide for Merseyside reflects typical costs in the North West, roughly 6% below the UK-wide figure. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £28,000–£42,500 |
| Higher specification | £42,500–£53,000 |
The biggest cost drivers are:
- Fire safety upgrades
- Floor and roof strengthening
- Staircase position
- Bathroom or not
Use the guide price tool to see how size and specification change the figure, then ask for a written, itemised quote.
Do you need planning permission for a rooflight loft conversion in Merseyside?
Before anything is built in Merseyside, we confirm which approvals apply in England. In England roof windows are permitted development if they project no more than 15 centimetres from the roof slope and side-facing windows are obscure-glazed. Listed buildings need consent.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
On a typical rooflight loft conversion we handle:
- Insulation between and under rafters
- Electrics, heating and plastering
- Drawings and structural calculations
- Head-height survey
- Roof windows installed
- Staircase and fire-safe escape route
How long does it take?
Allow 4 to 6 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in Merseyside
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
Towns we cover in Merseyside include Liverpool, Birkenhead, St Helens, Southport, Wallasey and Bootle.
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
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 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 Merseyside
Who approves a rooflight loft conversion in Merseyside?
Planning matters in Merseyside go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.
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.
How long does it take?
Usually 4 to 6 weeks on site.
How much does a rooflight loft conversion cost in Merseyside?
In Merseyside, a rooflight loft conversion typically costs £28,000–£42,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
