A loft conversion in the UK is one of the smartest investments homeowners can make. It adds valuable living space without extending the footprint of your home and can increase property value by up to 20–25%.
Whether you’re planning a new bedroom, home office, or master suite with en-suite, understanding the types of loft conversions and their costs is essential before starting.
In this guide, we explain the 4 main types of loft extensions in the UK, their average costs, and what affects pricing.
- Velux Loft Conversion (Rooflight Loft)
- Dormer Loft Conversion
- Hip to Gable Loft Conversion
- Mansard Loft Conversion
1. Velux Loft Conversion (Rooflight Loft)
A Velux loft conversion is the most affordable and simplest option. It uses roof windows without changing the roof structure.
Best for:
- Homes with good existing head height
- Budget-conscious projects
- Offices, guest rooms, or storage
Typical features:
- Roof windows only
- No dormers or roof extensions
- Usually no bathroom
Average Cost in the UK:
£48,000 – £50,000
2. Dormer Loft Conversion
A Dormer loft conversion adds a box-shaped extension to the roof, creating more headroom and usable floor space.
Best for:
- Adding a full bedroom + bathroom
- Terraced and semi-detached homes
- Families needing extra space
Typical features:
- Rear or side dormer
- Flat roof section
- Ideal for en-suites
Average Cost in the UK:
£60,000 – £65,000
3. Hip to Gable Loft Conversion
A Hip to Gable conversion extends the sloping roof side into a vertical wall, dramatically increasing internal space.
Best for:
- Semi-detached or detached houses
- Properties with hipped roofs
- Larger master bedrooms
Typical features:
- Major roof restructuring
- More floor area than dormer
- Often combined with rear dormer
Average Cost in the UK:
£70,000 – £75,000
4. Mansard Loft Conversion
A Mansard loft conversion is the most premium and complex option. It alters the entire roof structure to create near full-height walls.
Best for:
- Maximum space creation
- Luxury conversions
- Multiple rooms or suites
Typical features:
- Almost flat roof
- Full-width extension
- Planning permission required
Average Cost in the UK:
£120,000 – £150,000
What Affects Loft Conversion Costs in the UK?
Several factors influence your final quote:
- Size of loft area
- Roof type and height
- Planning permission
- Structural steel work
- Bathroom installation
- Staircase complexity
- Electrical and plumbing upgrades
- Fire safety regulations
- London vs rest of UK pricing
Do You Need Planning Permission?
| Loft Type | Planning Permission |
| Velux | Usually No |
| Dormer | Often No (rear only) |
| Hip to Gable | Usually Yes |
| Mansard | Always Yes |
Is a Loft Conversion Worth It?
A professionally built loft conversion in the UK:
- Adds 20–25% property value
- Cheaper than moving house
- Avoids stamp duty and legal fees
- Can be completed in 6–10 weeks
- Improves energy efficiency
Final Thoughts
Choosing the right loft conversion depends on:
- Your budget
- Your roof structure
- How much space you need
- Whether planning is required
From simple Velux lofts to luxury Mansard conversions, there is a solution for every home.
Looking for a Trusted Home Renovation Company in London?
At Home Construction and Renovation, we specialise in:
- Full house renovations
- Extensions and loft conversions
- Kitchens and bathrooms
- Property refurbishments
We provide:
- Fully insured services
- Transparent pricing
- Professional project management
- High-quality workmanship across London
If you’re planning a house renovation in London, contact us today for a free consultation and site visit.