If you’re considering expanding your living space in London, a loft conversion is one of the most cost-effective ways to add value and square footage to your home. But how much does a loft conversion cost in London?
At Crest Projects, we’ve helped hundreds of London homeowners transform their unused attic spaces into beautiful, functional rooms. In this comprehensive guide, we’ll break down:
✔ Average loft conversion costs in London
✔ 4 main types of loft conversions & their price differences
✔ Key factors that affect your final price
✔ How to save money on your project
✔ Why it’s still cheaper than moving in London
Let’s dive in!
Loft Conversion Cost in London: Price Breakdown
The average loft conversion cost in London ranges from £35,000 to £75,000, depending on the type, size, and specifications. Here’s a detailed breakdown:
| Type of Loft Conversion | Average Cost in London | Project Duration |
|---|---|---|
| Velux (Skylight) Conversion | £20,000 – £40,000 | 4-6 weeks |
| Dormer Conversion | £35,000 – £60,000 | 6-8 weeks |
| Hip-to-Gable Conversion | £40,000 – £65,000 | 7-9 weeks |
| Mansard Conversion | £45,000 – £75,000 | 8-10 weeks |
Prices include structural work, insulation, electrics, and basic finishes. High-end finishes (e.g., luxury bathrooms, bespoke storage) will increase costs.
4 Main Types of Loft Conversions & Their Costs
1. Velux (Skylight) Loft Conversion (£20k-£40k)
- Best for: Small lofts with good existing headroom
- Pros: Fastest & cheapest option, no major structural changes
- Cons: Limited extra space compared to other types
2. Dormer Loft Conversion (£35k-£60k)
- Best for: Most London terraced & semi-detached homes
- Pros: Adds significant floor space & headroom
- Cons: Requires more structural work than Velux
3. Hip-to-Gable Conversion (£40k-£65k)
- Best for: Detached or end-of-terrace homes
- Pros: Maximises usable space in sloping roof homes
- Cons: More complex than dormer conversions
4. Mansard Loft Conversion (£45k-£75k)
- Best for: Period properties & conservation areas
- Pros: Creates the most usable space
- Cons: Most expensive option, often needs planning permission
What Affects Your Loft Conversion Cost in London?
Several key factors influence your final price:
1. Size of Your Loft
- Small loft (20m²): £25k-£45k
- Medium loft (30m²): £35k-£60k
- Large loft (40m²+): £50k-£80k
2. Structural Work Needed
- Steel beams for support: £1,500-£4,000
- Floor reinforcement: £2,000-£5,000
- Roof alterations: £3,000-£8,000
3. Interior Finishes
- Basic finishes: Included in standard quote
- Mid-range (e.g., fitted storage): +£5k-£10k
- Luxury (e.g., en-suite bathroom): +£10k-£20k
4. Location in London
- Outer London (e.g., Croydon): 10-15% cheaper
- Central London (e.g., Kensington): 15-20% more expensive
How to Save Money on Your Loft Conversion
1. Choose a Velux or Dormer Conversion
These are typically 30-40% cheaper than mansard conversions.
2. Stick to Simple Layouts
Avoid complex designs with multiple rooms to reduce costs.
3. Use Standard Materials
Opt for off-the-shelf windows and doors instead of bespoke.
4. Get Multiple Quotes
Compare at least 3-4 quotes from reputable builders.
5. Plan Ahead
Unexpected changes mid-project can increase costs by 10-20%.
Is a Loft Conversion Cheaper Than Moving in London?
Yes! Here’s why:
| Option | Average Cost |
|---|---|
| Loft Conversion | £35k-£75k |
| Moving Costs (Stamp Duty + Fees) | £50k-£150k+ |
💡 Key Benefit: A loft conversion adds space and increases your home’s value by 15-20%, while moving comes with hefty taxes and fees.
Do You Need Planning Permission?
Most loft conversions in London fall under Permitted Development Rights, meaning:
✅ No planning permission needed (if within size limits)
✅ Still requires Building Regulations approval
⚠ Exceptions: Conservation areas & listed buildings usually need permission.
Why Choose Crest Projects for Your Loft Conversion?
✔ 10+ Years of London Experience
✔ Free, No-Obligation Quotes
✔ Full Planning & Building Regs Support
✔ Fixed-Price Contracts (No Hidden Costs)
✔ 5-Year Workmanship Guarantee
Frequently Asked Questions
1. How much value does a loft conversion add?
Typically 15-20% of your home’s current value.
2. Can I add a bathroom in my loft conversion?
Yes! An en-suite bathroom adds £8k-£15k to costs.
3. How long does a loft conversion take?
Most projects take 6-10 weeks from start to finish.
4. Is my loft suitable for conversion?
Most lofts with 2.2m+ headroom can be converted.
Ready to Get Started?
A loft conversion is one of the smartest home improvements you can make in London. At Crest Projects, we’ll guide you through every step – from design to completion.
📞 Contact us today for a FREE consultation & quote!
