Calculate your loft conversion cost
Loft conversion cost by type in Brighton
The national source benchmarks below are for typical 30m² projects.
UK £22,500–£30,000£25,850–£34,500
UK £40,000–£60,000£46,000–£69,000
UK £50,000–£70,000£57,500–£80,500
UK £50,000–£80,000£57,500–£92,000
What the regional adjustment changes
What can change a real Brighton quote?
- Velux, dormer, hip-to-gable, mansard or shell-only type
- Usable new floor area
- Roof structure and existing head height
- New staircase position and specification
- Structural steel and roof alterations
- Ensuite, electrics, heating and finish level
- Region, access and scaffolding
Local planning considerations
Coastal exposure, conservation areas, parking and restricted access can affect individual quotations beyond the broad South East planning model.
- Exterior specifications may need more attention where a property is exposed to coastal weather and salt-laden air.
- Tight street access or controlled parking can change waste, scaffold and delivery logistics even when the underlying project is unchanged.
- Check listed-building or conservation constraints before assuming a standard window, roof, rendering or extension specification.
How the regional model works
The 1.15× factor places this planning estimate 15% above the national planning baseline. We keep that modelling assumption separate from the dated national benchmark so users can see which part comes from an external source and which part is UK Home Costs modelling.
Sources
Loft Conversion Cost: 2026 UK Price Guide & Breakdown
Published / checked: March 2026
Used for: Loft conversion type benchmarks
Construction output price indices
Published / checked: 13 August 2026
Used for: Construction price trend and update checks
Frequently asked questions
How much does a loft conversion cost in Brighton in 2026?
Our modelled Brighton ranges run from about £25,850–£34,500 for a 30m² Velux or rooflight conversion to about £57,500–£92,000 for a 30m² mansard.
How much is a dormer loft conversion in Brighton?
The modelled planning range for a typical 30m² dormer is about £46,000–£69,000, starting from the current national £40,000–£60,000 benchmark.
Why is the Brighton estimate different from the UK benchmark?
The 1.15× South East factor places the model 15% above the national planning baseline. It is a planning assumption, not an observed city-wide contractor index.
What can push a loft conversion above the modelled range?
Staircase changes, structural steel, low head height, complex roof alterations, an ensuite, premium finishes, difficult access and fire-safety work can increase the final quote.