Cost of a Loft Conversion in London (2025 Guide)
How much does a loft conversion cost in London? The price depends on the type of conversion, size, specification, and finish. This guide gives you realistic figures — and a quick way to compare local builder quotes.
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Typical Cost of a Loft Conversion Prices
- ✓Velux/rooflight conversion: £15,000–£22,000
- ✓Dormer conversion: £25,000–£45,000
- ✓Hip-to-gable conversion: £30,000–£50,000
- ✓Mansard conversion: £40,000–£65,000
- ✓Adding an en suite: £4,000–£8,000 extra
- ✓Staircase (typical): £3,000–£6,000
Price Guide for London (2026)
Prices are indicative and vary by specification, materials, and access. Always compare at least 3 quotes — Quote2 makes this fast and free.
| Job / item | Typical cost (UK) |
|---|---|
| Velux / rooflight conversion | £15,000–£22,000 |
| Standard dormer conversion | £25,000–£45,000 |
| Hip-to-gable conversion | £30,000–£50,000 |
| Mansard conversion | £40,000–£65,000 |
| En suite addition | £4,000–£8,000 extra |
| New staircase (typical) | £3,000–£6,000 |
What affects loft conversion costs in London?
The biggest driver of loft conversion cost in London is the conversion type. A simple Velux conversion (using the existing roofline with rooflights) is the most affordable as it involves minimal structural change. Dormer conversions, which extend the roofline to create full head height, are the most popular and add more usable space. Hip-to-gable and mansard conversions are more structurally complex and expensive. Other cost factors include the size of the space, specification of finishes, whether an en suite is added, and the cost of building regulations approval. Always request a full breakdown in your Quote2 quotes.
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Frequently Asked Questions
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