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 Dunstable?
In Dunstable, a rooflight loft conversion typically costs £32,000–£47,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Building costs in the East of England run about 6% above the UK average, and the figures for Dunstable are adjusted to reflect that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £32,000–£47,500 |
| Higher specification | £47,500–£59,500 |
The main things that change the cost:
- Bathroom or not
- Fire safety upgrades
- Staircase position
- Storage and finishes
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 Dunstable?
The approval route for Dunstable is set by planning law 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.
Where work involves a shared wall, building on the boundary, or digging foundations within 3 metres of a neighbour’s building and deeper than its foundations (or within 6 metres for deeper work), the Party Wall etc. Act 1996 applies and notices must be served before work starts.
We check this for your address before design work starts, so there are no surprises later.
What we handle
From survey to sign-off, the job normally involves:
- Drawings and structural calculations
- Electrics, heating and plastering
- Roof windows installed
- Building control sign-off
- Staircase and fire-safe escape route
- Head-height survey
How long does it take?
Build time is typically 4 to 6 weeks on site. Design and approvals come first and typically take 6 to 12 weeks, depending on the approval route.
Building in Dunstable
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
Dunstable sits in Bedfordshire, about 15 miles south-east of Milton Keynes. We cover the whole of Dunstable, including postcodes LU6.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 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 Dunstable
How much does a rooflight loft conversion cost in Dunstable?
In Dunstable, a rooflight loft conversion typically costs £32,000–£47,500 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
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.
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
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 a rooflight loft conversion take in Dunstable?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
