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 St Helens?
In St Helens, a rooflight loft conversion typically costs £28,000–£42,500 for a typical rooflight conversion, including VAT at 20% (standard rate). That range is adjusted for the North West, where domestic building work typically costs around 6% below the national average. 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 main things that change the cost:
- Fire safety upgrades
- Bathroom or not
- Number of roof windows
- Floor and roof strengthening
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 St Helens?
Before anything is built in St Helens, 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.
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:
- Staircase and fire-safe escape route
- Head-height survey
- Building control sign-off
- Drawings and structural calculations
- Roof windows installed
- Floor joists and any steel beams
How long does it take?
Expect 4 to 6 weeks on site. Allow time beforehand for drawings and approvals, usually 6 to 12 weeks.
Building in St Helens
The North West has many brick terraces and inter-war semis, where kitchen extensions and dormer loft conversions add space without moving.
St Helens sits in Merseyside, about 10 miles east of Liverpool. We cover the whole of St Helens, including postcodes WA10.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 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 St Helens
How much does a rooflight loft conversion cost in St Helens?
In St Helens, 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.
How long does a rooflight loft conversion take in St Helens?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
Can I have a bathroom?
Yes, where there is enough head height at the shower or bath position.