Covering St Austell
St Austell sits 13 miles north-east of Truro, with Bodmin 9 miles to the north and Truro 13 miles to the south-west.
Projects in Cornwall are taken on by arrangement, and any travel and accommodation costs for the team are shown openly in the quote.
Homes in the South West
In the South West, matching local stone, render or slate is often the main design question, and conservation areas and listed buildings are common in historic towns.
What does a dormer loft conversion involve?
A dormer loft conversion builds a box-shaped extension out from the rear slope of the roof, creating vertical walls and full head height across most of the new floor. It is the most popular type of loft conversion because it gives the most usable space for the cost.
- Steelwork and new floor structure
- Dormer frame, roof covering and cladding
- Staircase, insulation and plasterboard
What is the guide price for a dormer loft conversion in St Austell?
Use these ranges to budget for dormer loft conversions; the survey turns them into a fixed price for the agreed specification.
| Dormer loft conversions | Guide price incl. VAT |
|---|---|
| Rear dormer, bedroom only | £50,000 to £65,000 |
| Full-width dormer with en-suite | £60,000 to £80,000 |
| L-shaped dormer (over rear outrigger) | £65,000 to £90,000 |
Planning and building rules in St Austell
English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.
In England many loft conversions are permitted development: the extra roof volume must stay within 40 m³ on a terraced house or 50 m³ on a semi or detached house, nothing can sit higher than the existing ridge, no dormer can face a road on the main elevation, and side windows must be obscure-glazed and non-opening below 1.7 m. Houses in conservation areas, National Parks and National Landscapes cannot use these roof-extension rights, so dormers there need planning permission (a rooflight-only conversion can still be permitted development), and flats always need permission.
What can affect a dormer loft conversion?
- A flat dormer roof needs proper falls and a quality membrane.
- L-shaped dormers are common on Victorian terraces with a rear outrigger.
How does the project run?
- Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
- Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.
Your questions answered
How much does a dormer loft conversion cost?
Typically £50,000 to £80,000 including VAT, and up to around £90,000 for an L-shaped dormer.
What cladding can a dormer have?
Tile-hanging to match the roof, render, slate, timber or zinc, depending on the house and any planning conditions.
Do you work in St Austell?
Yes. St Austell is within our coverage for dormer loft conversions, along with nearby Bodmin and Truro.
Also covering
- Dormer loft conversions in Bodmin
- Dormer loft conversions in Truro
- Dormer loft conversions in Falmouth
- Dormer loft conversions in Redruth
Learn more about dormer loft conversions, or see every project we cover in St Austell.

