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 Ashford, Surrey?
In Ashford, a rooflight loft conversion typically costs £33,500–£50,500 for a typical rooflight conversion, including VAT at 20% (standard rate). That range is adjusted for the South East, where domestic building work typically costs around 12% above the national average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £33,500–£50,500 |
| Higher specification | £50,500–£63,000 |
The main things that change the cost:
- Floor and roof strengthening
- Staircase position
- Fire safety upgrades
- Number of roof windows
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 rooflight loft conversion in Ashford, Surrey?
Whether you need planning permission depends on your house and its location 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
What we take care of:
- Building control sign-off
- Electrics, heating and plastering
- Drawings and structural calculations
- Staircase and fire-safe escape route
- Insulation between and under rafters
- Floor joists and any steel beams
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 Ashford, Surrey
Commuter towns across the South East have many 1930s and post-war semis that suit rear extensions and hip-to-gable loft conversions.
From TW15 outwards, we take on projects throughout Ashford and the surrounding parts of Surrey.
How it works
- 01
Survey and brief
We visit, discuss your ideas and budget, and survey the property or site at no cost.
- 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 handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about rooflight loft conversions in Ashford, Surrey
How much does a rooflight loft conversion cost in Ashford?
In Ashford, a rooflight loft conversion typically costs £33,500–£50,500 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 Ashford?
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.
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.
Does a rooflight loft conversion need planning permission?
Usually not. In England roof windows are permitted development if they project no more than 15 centimetres from the roof slope, sit no higher than the ridge and any side-facing windows are obscure-glazed. Listed buildings and houses whose rights have been removed need consent. Building regulations approval is always needed.
