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 Cambridgeshire?
In Cambridgeshire, 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 Cambridgeshire 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:
- Fire safety upgrades
- Storage and finishes
- Staircase position
- Number of roof windows
Your exact price depends on the survey and drawings. The guide price tool gives a quick range in the meantime.
Do you need planning permission for a rooflight loft conversion in Cambridgeshire?
Before anything is built in Cambridgeshire, 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.
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.
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:
- Electrics, heating and plastering
- Building control sign-off
- Drawings and structural calculations
- Floor joists and any steel beams
- Roof windows installed
- Head-height survey
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 Cambridgeshire
Across the East of England, 1930s and post-war semis, newer estates and rural cottages all feature, each with different extension and loft options.
Towns we cover in Cambridgeshire include Peterborough, Cambridge, Wisbech, St Neots, Huntingdon and March.
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 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 Cambridgeshire
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 Cambridgeshire?
In Cambridgeshire, 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.
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 a rooflight loft conversion take in Cambridgeshire?
Typically 4 to 6 weeks on site. Design and approvals beforehand usually take 6 to 12 weeks.
