Builders
Carpenters
Electricians
Flooring Specialists
Gardeners
Handymen
Heating Engineers
Painters & Decorators
Plasterers & Renderers
Plumbers
Roofers
Tilers
myLoft Conversion Cost in London
At a Glance
- The average loft conversion in London costs around £46,000.
- Most loft conversions in London take 4 to 10 weeks to complete.
- Velux conversions are the cheapest option, from around £23,000.
- Mansard conversions are the most expensive, averaging around £80,000.
- Average loft conversion costs in London by type and size.
- Extra costs to budget for, including scaffolding, staircases, and party wall agreements.
- How long a loft conversion typically takes in London.
- How MyJobQuote can help you get quotes from local contractors.
Get free estimates
Are you a trade? Get more work today!
A loft conversion is one of the best ways to add extra space to a London home, especially if moving away from a good school catchment or transport links isn't an option. Whether you need a spare bedroom, a home office, or space for a growing family, converting an unused loft can make a real difference without the upheaval of a house move.
This guide covers the average loft conversion cost in London, broken down by type and size, along with the extra costs and factors that are specific to converting a loft in the capital. A well-finished conversion can also add around 10% to 20% to your property's value.
For a more precise estimate based on your own property, try our loft conversion cost calculator before getting quotes.
£46,000
Table of Contents
What Is The Cost of a Loft Conversion in London?
How much does the average loft conversion in London cost?
The cost of a loft conversion in London depends on the type you choose, the size of the space, and the amount of structural work involved. A 30m² dormer conversion, one of the most popular choices in the capital, typically costs between £40,500 and £57,500. However, costs start at around £23,000 for a small Velux loft, rising to around £105,000 for a larger mansard conversion.
Loft conversion costs in London typically range from £1,800 to £2,700 per m², which is around 15% to 25% higher than the UK average, reflecting higher labour and material costs in the capital.
What are you planning to use your loft conversion for?
Bedroom/Guest room
16 votes - 80%80% of votes
Home office or study
2 votes - 10%10% of votes
Bathroom
1 votes - 5%5% of votes
Additional living space
1 votes - 5%5% of votes
20 votes
See results
Hide results
Loft Conversion Prices in London
Below are the average costs for the most common loft conversion types in London, based on a 30m² and 50m² project.
| Type of Conversion | Average Cost (30m²) | Average Cost (50m²) |
|---|---|---|
| Velux Loft Conversion | £23,000–£34,500 | £29,000–£46,000 |
| Dormer Loft Conversion | £40,500–£57,500 | £52,000–£80,500 |
| Hip-to-Gable Loft Conversion | £52,000–£69,000 | £63,500–£80,500 |
| Mansard Loft Conversion | £70,000–£90,000 | £85,000–£105,000 |
| L-Shaped Dormer Loft Conversion | £57,500–£69,000 | £63,500–£80,500 |
| Shell Loft Conversion | £23,000–£46,000 | £34,500–£63,500 |
Want a custom price?
Post your job
Cost of a Loft Conversion in London by Type
Velux Loft Conversion
A Velux conversion adds rooflights within your existing roofline, so no structural changes are needed. It's the fastest and most affordable option for a London loft, and it's usually covered by permitted development. Cost per m² is typically between £750 and £1,150 in London.
Dormer Loft Conversion
A dormer conversion builds a box-shaped structure into the pitched roof, creating a flat ceiling and much more usable floor space. It's a popular choice for London's Victorian and Edwardian terraces. Cost per m² is typically between £1,350 and £1,950 in London.
Hip-to-Gable Loft Conversion
This conversion replaces a sloping roof end with a vertical gable wall, creating a significant amount of extra space. It only works on semi-detached or detached homes with a hipped roof, which are more common in London's outer boroughs than in inner-city terraces. The average cost of a hip-to-gable loft conversion per m² is typically between £1,750 and £2,300 in London.
Mansard Loft Conversion
A mansard loft conversion changes the whole shape of the roof and creates the most additional space of any loft conversion type. It's a popular option for London's flat-fronted terraced houses. Cost per m² is typically between £2,300 and £3,000 in London, but can be more.
L-Shaped Dormer Loft Conversion
A L-shaped dormer combines a rear and side dormer to create a larger loft space that's well-suited to Victorian and Edwardian terraces. Cost per m² is typically between £1,900 and £2,300 in London.
Shell Loft Conversion
A shell loft conversion involves creating the basic structure of the loft without the final finishes. It's often chosen when the homeowner wants to have more control over the finishing touches or when they plan to do the work themselves. Cost per m² is typically between £750 and £1,550 in London.
What Type of Loft Conversion Suits Your London Property?
London's housing stock includes large numbers of Victorian and Edwardian terraces, along with many interwar and post-war semi-detached houses in the outer boroughs. The right loft conversion for your home often depends on which of these you have.
- Inner London terraces — Dormer and mansard loft conversions are often the most practical choice for Victorian and Edwardian terraces, as they maximise headroom and living space while working well with the existing roof structure.
- Outer London semis and detached homes — boroughs such as Bromley, Sutton, and Kingston have more semi-detached and detached properties with hipped roofs, making hip-to-gable conversions a practical option.
- Conservation areas — London has a high concentration of conservation areas and listed buildings, particularly in boroughs such as Westminster, Kensington and Chelsea, Islington, and Camden. Camden alone has around 40 conservation areas, covering roughly half the borough. Loft conversions in these areas are more likely to require planning permission or additional design considerations, with councils often expecting new roof materials to match the character of the existing building.
We're planning a dormer loft conversion on a 1930s semi. How long should we realistically budget for from start to finish? We'd need to stay in the house throughout.
"Where a planning is ready signed and money flow without any delays the dormer loft conversion should take no longer than 3 months from start to finish."
If you're weighing up costs across different parts of the country, our loft conversion cost guide for Manchester shows how prices in the north currently compare with London.
Additional Loft Conversion Costs in London
Budget for these additional costs on top of the main build. Some, like planning fees, are set nationally, and don't change by region. Others, like scaffolding and skip hire, tend to cost more in London due to limited parking and higher demand for tradespeople.
| Job Description | Average Price |
|---|---|
| Architectural drawings | £440–£1,650 |
| Structural engineer calculations | £650–£2,000 |
| Planning permission fees | £548 |
| Building regulations approval | £850–£1,350 |
| Party wall agreement (single surveyor) | £800–£1,000 |
| Party wall agreement (disputed, per surveyor) | £1,500+ |
| Scaffolding hire | £1,800–£4,000 |
| Skip hire | £230–£635 |
| Standard staircase installation | £1,650–£2,750 |
| Bespoke staircase installation | £5,500–£11,000 |
Want a custom price?
Post your job
Party wall agreements come up more often in London than in most of the UK, simply because so many homes are terraced or semi-detached and share a wall with a neighbour. If a neighbour disputes the work, each side may need to appoint their own surveyor, which is where costs can rise.
If you live in a controlled parking zone, you may also need a council permit to place a skip or scaffolding on the road outside your home. This adds a small extra cost and is worth arranging in advance.
How Long Does a Loft Conversion Take in London?
Most loft conversions in London take 4 to 10 weeks, though this can vary depending on the type of conversion, access to the property, and whether a party wall agreement or planning permission is needed. Conservation areas are more common in London than in most UK cities, which can add a few weeks if planning permission is required.
| Loft Type | Average Timescale |
|---|---|
| Velux | 4–6 Weeks |
| Dormer | 6–8 Weeks |
| Hip-to-Gable | 6–8 Weeks |
| Mansard | 8–10 Weeks |
Ask a Trade
Got a question that only a tradesperson can answer? We have thousands of trades ready to answer any question you may have.
Ask your question
Checklist: Hiring a Loft Conversion Builder in London
Hiring an experienced specialist helps ensure the work meets building regulations and is finished to a high standard. When comparing quotes from London tradespeople, check the following:
- Experience with similar loft conversions in London.
- Positive reviews from previous customers.
- Whether structural calculations are included in the quote.
- Knowledge of building regulations and, where relevant, conservation area rules.
- Whether they'll manage other trades and the party wall process.
- Timescales and payment terms.
- Relevant insurance cover.
- Guarantees for workmanship.
