Loft conversion: Cost breakdown 2025

Building up is a great way to create added living space in your home. But how much does a loft conversion cost? Here, you'll find everything you need to know to help budget for your home improvement project.

Loft conversions are a cost-effective way to add space and value to your property – whether you want an extra bedroom, a home office, or more usable space.

In December 2024, the UK government eased the rules on loft extensions, making it easier for homeowners to build loft extensions and add extra storeys. But, how much might it cost?

Here, you'll find a comprehensive breakdown of costs for different loft conversion types – including materials, professional fees and services, and more.

How much does a loft conversion cost in 2025?

Loft conversion costs in the UK vary significantly depending on loft conversion types and the size and complexity of the job.

The average loft conversion costs in the UK for a 30m² loft space are:

• Velux loft conversion – £27,500

• Dormer loft conversion – £50,000

• Hip-to-gable loft conversion – £60,000

• Modular loft conversion – £45,000

• Mansard loft conversion – £65,000

• Shell loft conversion –£30,000

• Bungalow loft conversion (50m²) – £75,000

Not sure which type of loft conversion is right for you and your home? Take a look at our handy guide to loft conversion types.

Are loft conversions worth it?

A loft conversion can add value and space. That said, cost-effectiveness varies by location and conversion type – especially with planning and building regulations affecting the total cost.

If you're wondering whether a loft conversion is worth it, here are some key points to consider:

• Increased property value often exceeds the conversion cost

• Additional living space ideal for bedrooms, offices, or playrooms

• Potential rental income if you design the conversion as a self-contained unit

• Disruption during construction can be a pain and requires careful planning

• Cost variations will depend on the project complexity and standard of materials

Average cost of a loft conversion UK

We've outlined a breakdown of a typical 30m² loft conversion project to help you understand the various costs involved.

Bear in mind that there could be additional costs for your particular project, so take the time to plan your loft conversion carefully before you get started.

We recommend speaking to experienced loft conversion companies near you. They'll be able to provide professional advice and guidance for your project on everything from costs and building regulations to Party Wall Agreements and project management.

Your guide to loft conversion planning

Keen to expand your home by going into the loft? The first step is loft conversion planning. Here's all you need to know.

Learn more

Loft conversion cost per m²

To help you calculate the cost of your loft conversion, here are the average loft conversion costs per m² in the UK – based on loft conversion types:

• Velux – £920 per m²

• Dormer – £1,670 per m²

• Hip-to-gable – £2,000 per m²

• Modular – £1,500 per m²

• Mansard – £2,170 per m²

• Shell – £1,000 per m²

• Bungalow (50m²) – £1,500 per m²

Types of loft conversion

Here's a rundown of the most popular loft conversion types in the UK.

Velux loft conversion

If you want to keep things simple or you're wondering what's the cheapest way to convert a loft, consider a Velux loft conversion.

A Velux loft conversion:

• Involves installing roof windows to let in plenty of natural light without altering the roof's structure

• As you don't change the roof structure, it's only really suitable for properties with large existing loft spaces

• It's the least disruptive type of loft conversion and the most affordable, but it provides the least amount of additional space

Velux loft conversion costs tend to average around £27,500.

Is my house suitable for a loft conversion?

Across the UK, homeowners are constantly looking for more space and loft conversions have become a popular project to gain living space without having to build an extension or move house. But you may be asking “is my house suitable for a loft conversion?”

Learn more

Dormer loft conversion

A dormer loft conversion extends your existing roof to create additional headroom and floor space. It's a versatile choice that's suitable for most types of property.

The average cost of a dormer loft conversion is around £50,000.

Hip-to-gable loft conversion

A hip-to-gable loft conversion is often seen on semi-detached or end-of-terraced homes. It involves extending the sloping side of the roof to create a vertical wall.

The average cost of a hip-to-gable loft conversion is roughly £60,000.

Modular loft conversion

A modular loft conversion involves using a prefabricated unit that's built off-site to minimise disruption and construction time. It’s then delivered to your property and attached to the existing roof structure.

Prices vary depending on the size, specifications, and complexity of the module but expect to pay in the region of £45,000.

Mansard loft conversion

A Mansard loft conversion involves significant structural changes to maximise space and headroom. The shape of the roof is changed to create a nearly vertical wall.

Mansard loft conversions are typically the most expensive option and tend to cost around £65,000.

Shell loft conversion

A shell or 'part loft conversion' is a basic loft conversion where all major structural work is carried out, including the new structural floor, joists, and dormer(s).

The interior design and finishes are then left for the homeowner (or another third-party tradesperson) to complete.

This type of conversion is perfect for homeowners who love DIY or have a limited budget. As the most basic loft conversion, the cost is generally more affordable.

The average shell loft conversion cost comes in at around £30,000.

Bungalow

Bungalows have a huge range of options from simple Velux conversions to expansive Mansard conversions as they often have a larger footprint.

However, due to the increased footprint, the average cost of a loft conversion on a bungalow can be higher, at around £75,000

Semi-detached house

A Velux or dormer extension would be cheaper and easier, but a hip-to-gable extension would give you the most space

The average cost for loft conversion on a semi-detached house is around £50,000

Detached house

In many detached houses, you can often combine several types of loft conversion: Velux roof windows at the front with a gable end and a flat roof dormer.

This allows you to increase loft space considerably, allowing room for a new bedroom and staircase.

The average cost of a loft conversion on a detached property is higher than a semi-detached, at around £62,500, but the investment will be returned in increased property value

Terraced house

Dormer loft conversions are popular with mid-terraced properties or hip-to-gable conversions for end-of-terrace homes.

A dormer loft conversion in a terraced house typically costs around £50,000.

Find a loft conversion specialist near me

There are two main drivers for wanting a loft conversion: to maximise the living space in your home and to increase its value. Add to that the fact that planning permission is rarely required, you'll add some magnificent views. And, in most cases, it's easier and more cost-effective than moving

Learn more

Factors affecting loft conversion costs

Here are some of the key factors that will affect the total cost of your loft conversion:

Size of the loft

The cost is directly related to the size of the loft. A larger space will naturally require more materials and labour, increasing the overall expense.

Complexity of the layout

If the layout involves intricate designs or multiple rooms, it will increase the costs due to the additional planning and construction work needed.

Additional materials and features

Several features can impact how much your loft conversion costs, including:

Stairs

The type of staircase you choose will affect the material and labour costs.

Any structural modifications will add to the overall cost and the age of your property may also limit the types of stairs that are suitable.

Flooring

The type and quality of flooring you choose will affect material costs. You'll also need to factor in additional costs if the existing floor joists require structural work.

Insulation

Similarly to flooring, the type and quality of insulation you choose will determine any additional insulation costs.

The complexity of the roof structure and the age of the property will also affect the insulation cost.

Glazing

If you're installing or replacing windows as part of your loft conversion, you'll need to budget for glazing.

The size and type of windows, including skylights or dormer windows, will contribute to the overall cost.

Type of loft conversion

As you'll have seen from the average costs listed above, the type of loft conversion you choose will have one of the biggest impacts on the loft conversion cost.

That's because the type of loft conversion will dictate the complexity and total duration of the project – which, in turn, affects the cost.

Project length

The length of the loft conversion project is influenced by the size of the loft, the complexity of the layout, and the availability of materials and labour.

In turn, the length of the project directly impacts the total labour costs.

Regional cost variations

As with most home improvement projects, regional variations in the costs of materials and professional services will significantly affect the total cost of your loft conversion project.

Most noticeably, the cost of labour and materials can differ considerably in different parts of the country – with London and the South East often being the most expensive region.

Style and quality of your fixtures and fittings

As you might expect, opting for more unique or high-end fixtures and fittings will increase the overall cost of your loft conversion.

Make sure you budget appropriately for the standard of fixtures and fittings that you're planning to buy.

How to reduce loft conversion costs

With a big project like a loft or attic conversion, it's easy for costs to spiral. Here are some of our top tips for reducing costs when converting a loft:

1. Effective planning and budgeting – Plan ahead to avoid unforeseen costs and create a clear budget to avoid unnecessary stress. Map in a contingency of 10% of your budget for unexpected costs

2. Hiring experienced, specialist contractors – From architects to building contractors, do your research and hire wisely to ensure top-quality service, efficiency, and, potentially, cost-savings

3. Consider some DIY – Could your organisational skills save you money in project management costs, or your DIY experience be put to good use to save on jobs such as tiling or painting?

4. Opt for a simpler design - Minimise structural costs with a simpler Velux loft conversion or attic conversion

5. Choose materials wisely - If you need to reduce costs, look at reclaimed materials such as wood, tiles, or second-hand furniture- it's great for the environment too

6. Be savvy with space - Save money on new furniture by enquiring about the cost of built-in units - it's often a great way to utilise those awkward nooks around a chimney or above the stairs too

On Checkatrade, you'll only find trades who meet our high standards and pass up to 12 checks.

Hidden costs to consider

When budgeting for the cost of a loft conversion, there are several other expenses to be aware of.

Project complexity

Most loft conversion cost estimates will be based on a relatively straightforward conversion process.

However, if your loft conversion is more complex for any reason then you can expect that to increase the total cost.

Age and condition of your property

The older your property and the worse the condition, the more you can expect to pay for your loft conversion.

That's because it increases the need for structural or repair work as part of the conversion process.

Legal costs and documentation

If you need to gain planning permission or obtain a Party Wall Agreement then you'll most likely incur additional legal costs as part of the process.

It's worth discussing likely legal costs and documentation with your loft conversion company when they quote you for the job – so you know those costs are factored in.

Architecture fees

Not all building contractors will need full architect plans but it’s always a good idea to get them drawn up so all contractors are clear on the project scope.

When it comes to loft conversion architect costs, simple architect plans will cost around £1,000, with more detailed plans costing up to £2,000.

How to find local experienced architects

If you need the help of a loft conversion architect, we can help you find experienced professionals in your area.

To get you started, read our top tips for finding experienced architects near you.

Ecological surveys

In the UK, ecological surveys can add to the overall cost of a loft conversion, particularly if protected species are present.

For example, if bats live in your loft/roof, you’ll need to get an official bat survey done to obtain a license to proceed with your loft conversion work.

A bat survey generally costs about £400 - £750.

Get a quote for your loft conversion

For accurate loft or attic conversion costs in your area, we recommend contacting several loft conversion companies near you to request a quote.

Loft conversion checklist

• Decide what you need the space for and research options and loft conversion ideas

• Plan, plan, plan. Loft conversions can be complicated, so it’s important to be in control and plan your loft conversion project

• Calculate your budget and add a 10% contingency

• Contact your local planning office to confirm if you’ll need planning permission

• Speak to local builders for advice and discuss viable options

• Ask friends and family for recommendations of local loft conversion specialists

• Shop around for fair and competitive prices

• When hiring a professional always choose tradespeople registered with a Competent Persons Scheme with relevant loft conversion experience, qualifications, and accreditations

• Ensure you receive a completion certificate from Building Control following a final inspection once the conversion is complete

Find the best loft conversion experts near you

Ready to start planning your loft conversion? We always recommend getting at least three quotes from specialist loft conversion companies in your area.

That way, you can compare prices and ensure you receive a fair and competitive price for the job.

All Checkatrade tradespeople are checked and approved, all customer reviews are verified, and every member must hold valid insurance.

To connect with quality loft conversion experts in your area, search your postcode, below:

FAQs

Do I need planning permission for a loft conversion?

Not necessarily. In most cases, a straightforward loft conversion is considered ‘Permitted Development’, providing it meets certain criteria. This means it shouldn’t need planning permission.

That said, if you’re planning on extending beyond the specified conditions of Permitted Development, you live in a conservation area, or you have a listed property, then you will need to apply for planning permission before you start work.

What is the cheapest way to do a loft conversion?

As a general rule, the cheapest way of converting a loft is to carry out a Velux loft conversion.

Effectively, you're simply working with the existing dimensions of your attic space by reinforcing the loft floor and installing roof lights.

Typically, a Velux loft conversion costs from around £22,500.

Can I do a loft conversion for 10K?

While unlikely for a full conversion, a small-scale attic conversion simply used for storage might be possible within this budget.

Can I reduce the cost of a loft conversion?

Choose cost-effective materials, simplify your design, and focus on essential features to minimise your spend. Compare quotes from several local specialists to ensure you get a fair and competitive price for the work.

Does a loft conversion add value to a house?

Yes, if done properly, a loft conversion can add up to 20 - 24.5% to the value of your property. Find out more in our handy guide: Add value to your home with a loft conversion

What's the most expensive part of a loft conversion?

Usually, the biggest chunk of your budget will be spent on the labour cost of the contractors you hire. Labour typically accounts for around 30% of the total cost of a loft conversion.

The second most expensive part of a loft conversion is usually materials, which account for around 20% of an average loft conversion. This cost can vary hugely depending on the quality and quantity of materials used.

How much is a loft conversion in London?

As with all home improvement projects, loft conversion costs will vary across the UK. And, as you might expect, in London costs are usually higher.

You can expect to pay the upper end of our cost estimates for converting a loft in a London property:

• Velux loft conversion – £30,000

• Dormer loft conversion – £60,000

• Hip-to-gable loft conversion – £70,000

• Bungalow (50m2) loft conversion – £87,500

• Modular loft conversion – £60,000

• Mansard loft conversion – £80,000

• Shell loft conversion – £37,500

How do people afford loft conversions?

There's no denying that any loft conversion will need a fairly hefty budget. But there are various ways to cover the cost of your loft conversion:

• Personal savings

• Take out a loan (secured or unsecured) to cover the costs

• Remortgage your home to get extra budget

• Pay some of the smaller loft conversion costs on a credit card (ideally one that offers deferred payments or a period of 0%)

Before undergoing any loft conversion project, make sure that can comfortably afford the costs involved.

How long does a loft conversion take?

Depending on the size and complexity of the conversion, it should take approximately 6-10 weeks to complete. This is from when construction starts, once you’ve obtained any necessary planning permission.

Can I live in my home during the conversion?

Yes, most people can stay in their homes while a loft conversion is being carried out.

What type of loft cannot be converted?

Although many lofts are suitable for conversion, not all homes can have a loft conversion.

Some of the reasons that might stop you from a loft conversion in your home are:

• The ridge height of your loft (if you have a low roof ridge height you may need a roof lift loft conversion)

• Any restrictions with roof alterations that apply to the building

• The existing roof/loft structure of the property

• If your home is located in a conservation area

To find out if your home is suitable for a loft conversion, speak to your local planning office or loft conversion experts in your area.