Builders
Carpenters
Electricians
Flooring Specialists
Gardeners
Handymen
Heating Engineers
Painters & Decorators
Plasterers & Renderers
Plumbers
Roofers
Tilers
myAverage Cost of a Loft Conversion in London | Average Prices 2026
At a glance
- The average loft conversion in London costs around £75,000
- Depending on the complexity of the job, it normally takes between 4 and 10 weeks
- Types of loft conversions available and their costs
- How long the job takes and what’s typically involved
Get free estimates
Are you a trade? Get more work today!
Loft conversions are popular in London because they are the perfect way to create more space without having to move out of a house you love, especially if you’re close to public transport and good schools.
Loft conversions are the ideal way to make the most of an unused space in your home. A 30m2 dormer conversion in London will cost on average, between £60,000 and £69,500.
That should give a large room with an en-suite, which you can use as a guest room, or an extra bedroom for your growing family. You could also use the conversion as an entertainment space, installing a home cinema or a gym. It could even be converted into a home office away from the distractions of family life.
To find out the likely cost of a loft conversion for your property, it’s best to get quotes from local loft conversion specialists in London who can help you to plan a loft conversion according to your budget.
£75,000
Table of Contents
- Average Cost of a Loft Conversion in London
- Factors Affecting Loft Conversion Costs
- Loft Conversion Types and Costs
- Additional Costs to Consider
- Do You Need Planning Permission for a Loft Conversion in London?
- How Long Does a Loft Conversion Take?
- Benefits of a Loft Conversion
- Hiring a Loft Conversion Specialist in London
- Get Quotes
Average Cost of a Loft Conversion in London
The total cost of a loft conversion depends on the type of loft you choose to have built and the structural work that will need to be done. Other factors that will affect the price include:
- The type of property
- Whether the roof is in good or poor condition
- The ease of access
- The build specification
- The trades required
Velux Conversion – A Velux conversion will be the most cost-effective option, especially if you are on a budget.
Dormer Conversion – Dormer’s are more expensive than Velux lofts, but they provide an increased amount of floor space.
Hip-to-Gable Conversion – This loft conversion is more expensive because it involves structural changes to the roof.
Mansard Conversion– A Mansard conversion is the most expensive loft type because it gives you much more space but involves major structural changes.
Below you can see the average costs of the most common loft types. Prices for a loft conversion in London are on average, between £1,800 and £2,700 per m2. This is between 20% and 25% higher than in other parts of the UK.
| Loft Choice | Size | Cost Per m2 | Average Cost |
|---|---|---|---|
| Velux | 20m2 | £1,800-£2,100 | £36,000-£42,000 |
| Velux | 30m2 | £1,800-£2,100 | £54,500-£63,000 |
| Dormer | 20m2 | £2,000-£2,300 | £40,000-£46,000 |
| Dormer | 30m2 | £2,000-£2,300 | £60,000-£69,500 |
| Hip-to-Gable | 30m2 | £2,200-£2,500 | £66,000-£75,000 |
| Hip-to-Gable | 50m2 | £2,200-£2,500 | £110,000-£125,000 |
| Mansard | 30m2 | £2,400-£2,700 | £72,000-£81,000 |
| Mansard | 50m2 | £2,400-£2,700 | £120,000-£135,000 |
| L-Shaped Dormer Loft | 30m2 | £2,100-£2,400 | £63,000-£72,000 |
| L-Shaped Dormer Loft | 50m2 | £2,100-£2,400 | £105,000-£120,000 |
| Adding en-suite | All Sizes | Not Applicable | £5,000-£12,000 |
Factors Affecting Loft Conversion Costs
London properties are all different and that’s why loft conversion prices even in similar houses are never the same.
The cost depends on several factors. For example, a loft that is a reasonable height and easy to access will very often cost less than a loft with a complex structure that is hard to access.
Your property’s location also has an influence. If builders are unable to park close to your home, then bringing in and taking out materials will be slower and this will increase labour costs.
Other factors that will have a bearing on the final price include:
- The type of conversion you choose to have built
- Loft size
- Roof structure
- The roof pitch and the available head height
- If steel beams are needed (they often are a requirement to strengthen floors and walls)
- The type of staircase installation
- The amount of Insulation and ventilation work
- The Electrical work
- Plumbing
- The addition of a bathroom or en-suite
- The quality of fixtures and finishes
- Scaffolding hire
- Waste removal (usually skip hire)
- Access to the property
Loft Conversion Types and Costs
Velux Conversion
A Velux conversion doesn’t need any structural modifications. The floor is reinforced, walls are insulated and windows are added, but you don’t get any extra space. Cost per m2 on average is between £1,800 and £2,100
Dormer Conversion
A dormer is a box structure within the pitched roof. You get a larger space with a flat ceiling. Cost per m2 on average is between £2,000 and £2,300
Hip-to-Gable Conversion
The sloping end of the roof is replaced with a gable wall. The modifications mean you get a lot more space. Cost per m2 on average is between £2,200 and £2,500
Mansard Conversion
The mansard creates the maximum amount of room possible. The roof shape is changed completely, and it requires major structural work, which is why it is the most expensive of the loft conversion types. Cost per m2 on average is between £2,400 and £2,700but can be more.
Additional Costs to Consider
There are additional costs you will need to add to your budget when you are planning a loft conversion in London. Below are some of the most common costs. Many are obligatory and so will apply to you, others are a matter of choice.
| Additional cost | Average price | Notes |
|---|---|---|
| Scaffolding hire | £2,480-£9,156 | between 4 to 10 weeks is approximately |
| Staircase installation | £1,500 and £10,000 | An off-the shelf option is cheaper than a custom-made staircase |
| Skip hire | £200 and £550 | on average, depending on the size of the skip required |
| Planning permission fees | £1250-£2,000 | not always needed, but if required will be between |
| Building regulations approval | £300 and £2,000 | depending on your property |
| Party wall agreements | £800 and £1,000 | If it is disputed costs can rise to more than double |
| Architectural drawings | £400 and £1500 | (not obligatory) These can cost between £400 and £1500 |
| Structural engineer calculations | £600-£1,800 | Calculations (obligatory) on average cost between £600 - £1,800 |
Do You Need Planning Permission for a Loft Conversion in London?
In most cases it isn’t necessary to get planning permission unless you live in a conservation area or a listed building. As long as the conversion meets with the following planning regulations:
- The new roof space cannot be larger than 40m³ for a terraced home and 50m³ for a detached or semi-detached property
- There can’t be any raised platforms, balconies or verandas added to the construction and the materials used must be similar to the original building
- The conversion must not increase the roof height or extend beyond the existing roof slope at the front of the house
- Side-facing upper-floor windows must be glazed with obscure glass and must also be non-opening if they are less than 1.7 metres above the floor level
All loft conversions in London must comply with building regulations for:
- Fire safety
- Insulation
- Ventilation
- Structural integrity
- Staircase design
How Long Does a Loft Conversion Take?
The amount of time it takes to build a loft conversion in London depends on a number of factors and these include:
- The weather
- The amount of structural work
- Planning permission (if needed)
- Party Wall agreement – If disputed this will delay the start of the loft conversion
- The timescales of other trades
- The level of finish (this can often add between 1-3 weeks)
| Loft Type | Average Timescale |
|---|---|
| Velux | 4-6 Weeks |
| Dormer | 6-8 Weeks |
| Hip-to-Gable | 6-8 Weeks |
| Mansard | 8-10 Weeks |
Benefits of a Loft Conversion
A loft conversion in London, is the perfect solution if you don’t want to move home but you need more space for your growing family.
A high-quality loft conversion should increase the value of your property by between 15% and 20% depending on where you live and the type of property you own. For example, a good quality loft conversion in London may add around £38,000to the value of your home.
The extra space created from a loft conversion can be used for a spare bedroom, a home office, a gym, a teenager’s den or an entertainment space, whatever you choose.
Hiring a Loft Conversion Specialist in London
Hiring a professional loft conversion specialist in London will ensure that the conversion meets the regulations and standards of building control.
Find London loft conversion specialists to hire by using MyJobQuote. When you are comparing quotes check the following:
- Experience building similar loft conversions
- Positive reviews from previous customers
- That structural calculations are included or not
- They have good knowledge of building regulations
- Whether they will manage other trades involved in the project
- Timescales and payment terms
- Relevant insurance cover
- Guarantees for workmanship
MyJobQuote can get you up to 3 quotes from loft conversion specialists in London which means you can compare prices and services easily.
It also means you can browse the profiles of specialists near you and read the reviews of previous customers. This will help you to choose a loft conversion specialist in London that meets your budget and has availability to start the job at your convenience.
Get Quotes
The total cost of a loft conversion in London depends on the type of conversion, the structure, finish and any additional features such as an additional bathroom.
The easiest way to find out about the cost is to post your job on MyJobQuote to receive no obligation quotes from local loft conversion specialists in London.
