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 Wiltshire?
In Wiltshire, a rooflight loft conversion typically costs £30,500–£46,000 for a typical rooflight conversion, including VAT at 20% (standard rate). Prices in the South West sit near the national average for this kind of work, and the range for Wiltshire reflects that. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| A typical rooflight conversion | £30,500–£46,000 |
| Higher specification | £46,000–£57,500 |
The biggest cost drivers are:
- Storage and finishes
- Staircase position
- Bathroom or not
- Fire safety upgrades
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 Wiltshire?
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.
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
From survey to sign-off, the job normally involves:
- Head-height survey
- Drawings and structural calculations
- Electrics, heating and plastering
- Insulation between and under rafters
- Staircase and fire-safe escape route
- Roof windows installed
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 Wiltshire
In parts of the South West, protected landscapes and conservation areas shape what can be built, so materials and roof forms are chosen carefully.
Towns we cover in Wiltshire include Swindon, Salisbury, Trowbridge, Chippenham and Melksham.
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
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 Wiltshire
What about fire safety?
The same escape rules apply as for any loft conversion, so a protected stairway and smoke alarms are typically needed.
Who approves a rooflight loft conversion in Wiltshire?
Planning matters in Wiltshire go to the council covering your address, and the work needs building control approval. We prepare and submit the applications for you.
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.
How much does a rooflight loft conversion cost in Wiltshire?
In Wiltshire, a rooflight loft conversion typically costs £30,500–£46,000 for a typical rooflight conversion, including VAT at 20% (standard rate). Your fixed price depends on the survey and drawings.