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 Derby?
In Derby, a rooflight loft conversion typically costs £28,500–£43,000 for a typical rooflight conversion, including VAT at 20% (standard rate). Prices across the East Midlands are typically 5% below the UK average for this kind of work, which is reflected in the range for Derby. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £28,500–£43,000 |
| Higher specification | £43,000–£54,000 |
The main things that change the cost:
- Floor and roof strengthening
- Number of roof windows
- Bathroom or not
- Fire safety upgrades
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 Derby?
Here is how the rules work for a rooflight loft conversion 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
The work we manage on a rooflight loft conversion:
- Roof windows installed
- Electrics, heating and plastering
- Head-height survey
- Insulation between and under rafters
- Staircase and fire-safe escape route
- Drawings and structural calculations
How long does it take?
Expect 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 Derby
In the East Midlands, many estates built since the 1960s have integral garages that convert well into a study or bedroom.
If your home is in Derby or close by in Belper, Ilkeston and Heanor, a free home visit is the first step.
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 handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about rooflight loft conversions in Derby
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 does a rooflight loft conversion cost in Derby?
In Derby, a rooflight loft conversion typically costs £28,500–£43,000 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.
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.
Is it cheaper than a dormer?
Yes, usually, because the roof shape stays the same. But you gain less full-height floor space.
Who approves a rooflight loft conversion in Derby?
Planning matters in Derby go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.