How Much Does Loft Conversion Cost in 2025?
Average cost in United Kingdom
£20,000 - £50,000
Typical average: £35,000
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Loft Conversion Cost by Country
| Country | Low | Average | High |
|---|---|---|---|
| 🇬🇧United Kingdom | £20,000 | £35,000 | £50,000 |
| 🇺🇸United States | $40,000 | $60,000 | $80,000 |
| 🇦🇺Australia | A$50,000 | A$75,000 | A$100,000 |
| 🇨🇦Canada | C$50,000 | C$70,000 | C$90,000 |
Loft Conversion Cost Breakdown
| Item | 🇬🇧 UK | 🇺🇸 US |
|---|---|---|
| Velux/rooflight conversion | £20,000-30,000 | $35,000-50,000 |
| Dormer conversion | £35,000-50,000 | $50,000-75,000 |
| Hip-to-gable | £45,000-60,000 | $60,000-85,000 |
| Mansard conversion | £50,000-75,000 | $70,000-100,000 |
| En-suite bathroom | +£4,000-8,000 | +$8,000-15,000 |
What Affects Loft Conversion Cost?
Conversion type
Size of loft
Structural requirements
En-suite bathroom included
Planning permission needed
Frequently Asked Questions
Many loft conversions fall under permitted development (no planning needed). Dormers to the front, mansard conversions, and conservation areas typically require planning permission.
Velux conversions take 4-6 weeks. Dormers take 6-8 weeks. Complex conversions (mansard, hip-to-gable) take 8-12 weeks.
A well-designed loft conversion can add 15-20% to your home value. In expensive areas, this can mean a significant return on investment.
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