How much does a loft conversion cost?

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Whether you’re looking to expand your living space or just fancy a room with a view, a loft conversion is a great addition to your home. Curious about what costs to expect? Note that the average cost of a loft conversion in the UK is around £50,000. Below, we’ve broken down prices across a range of different conversions and properties. All prices are accurate as of 2024.

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A loft conversion can completely transform your home, adding extra space that you can use for a bedroom, office, storage and more. Before you embark on a loft conversion, it’s important to understand costs, so that you can budget accordingly and prepare for the work to begin.

To get the most accurate quotes from your builder, be sure you have a clear idea of exactly what you want from your loft conversion. Below, we’ve broken down the costs you might expect across different types of loft conversions.

We'll cover the following topics in this pricing guide:

  1. Average loft conversion costs
  2. Cost of loft conversion per type
  3. How long does a loft conversion take?
  4. How to reduce loft conversion costs
  5. FAQ
  6. Your loft conversion checklist
loft-extension-costs

Average loft conversion costs

When you want to expand the size of your home but can’t afford to move or aren’t able to build an extension, sometimes the only way is up. By converting your loft, you can gain more space for a bedroom, home office or just some extra storage.

Below, we’ve outlined the average costs of basic loft conversions across a range of types of conversions and types of properties. By gaining knowledge about what kind of prices to expect, this will help when consulting with tradespeople and suppliers about different quotes and additional costs. These prices are all averages though, so if you want a more detailed breakdown of loft conversion costs, keep reading.

Type of Loft ConversionAverage Cost Range
Velux loft conversion£22,500 to £30,000
Dormer loft conversion£40,000 to £60,000
Hip to gable loft conversion£50,000 to £70,000
Mansard loft conversion£50,000 to £80,000
Modular loft conversion£50,000
Shell loft conversion£30,000
DIY partial loft conversion£50,000
Semi-detached house loft conversion£50,000
Detached house conversion£62,500
Bungalow house conversion£62,500 to £87,500

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Cost of loft conversion per type

How much does a loft conversion cost?

The average cost of a loft conversion is £50,000. Although this is the average, costs will vary based on the different types of conversions available. Below, we talk you through exactly what types of conversion you might want, and how much it could cost you.

Additional factors that will affect the cost of your conversion include:

  • Size of the loft
  • Existing roof structure
  • Finishings
  • How long the project takes
  • Your location

Usually, the larger the space, and the more finishings such as flooring and insulation, the more you will pay. Cost will also be determined based on the specifics of your property and the average costs in your local area, with urban areas usually demanding higher prices. If you search for a builder through MyBuilder, you can compare quotes from a range of local tradespeople, so that you can get the best quote in your location.

Cost of a Velux loft conversion

A Velux loft conversion involves converting the existing space, without making changes to the roof structure. You can expect to pay between £22,500 and £30,000 for a Velux loft conversion.

This is the cheapest option for a loft conversion; however, this also provides the least amount of extra space. As this option involves working with the space you already have, this is best suited to loft spaces that already have the ideal dimensions for how you intend to use it.

Cost of a dormer loft conversion

A dormer loft conversion involves adding a box shaped structure to a pitched roof. This can expand both floor and overhead space. With a dormer loft conversion, you can expect to pay between £40,000 and £60,000.

This is a great option if you want more room than your current loft space, but also costs less in comparison to other, more extensive expansions.

Cost of a hip to gable loft conversion

A hip to gable loft conversion uses an already existing slanted end roof to create a vertical wall, changing a hip roof into a gable roof. This type of conversion is ideal for an end of terrace or detached house.

For a hip to gable loft conversion, you can expect to pay between £50,000 and £70,000.

Cost of a mansard loft conversion

Typically built at the back of your property, mansard loft conversions have horizontal roofs, which are built on top of an existing roof structure. For a mansard loft conversion, you can expect to pay between £50,000 and £80,000. While this is one of the more expensive options, it provides a significant amount of space compared to other, cheaper conversions.

For mansard loft conversions, you will also always require planning permission, so be sure to seek this out when planning your conversion.

Cost of a modular loft conversion

A modular loft conversion involves building sections of the conversion off-site, which are then attached in sections known as modules. These are then built into the structure. A modular loft conversion is far quicker than other loft conversions and can be a great option if you need your conversion completed quickly.

However, to allow for tradespeople to get exact measurements, you will need to clear and prepare your space well in advance. Modular loft conversions are also more affected by bad weather and will wear faster than other conversions.

A modular loft conversion also requires space surrounding your property, which could require road closures and disruption to neighbours. A modular loft conversion will also usually require planning permission. So, before choosing, be sure to consult with your local loft conversion specialist about which options will suit your property and your needs best.

For a modular loft conversion, you can expect to pay around £50,000.

Shell loft conversion

A shell loft conversion involves all major structural work being carried out by a builder, including beams, new floors and dormers. The final touches and interior design are then left to the homeowner.

This type of conversion is great for someone who is capable at DIY projects or has a limited budget. The shell loft is one of the most affordable loft conversions available. On average, you can expect to pay around £30,000 for a shell loft conversion.

Cost a partial DIY loft conversion

If you’re looking to do part of a loft conversion yourself, here’s a breakdown of the costs associated with completing it. When completing a project on your own, be sure to consult with tradespeople for complicated tasks such as plumbing and electrics. If you have any doubts about the structural integrity of your conversion, be sure to consult with professional tradespeople to avoid dangerous or faulty structures in your home.

Loft Conversion TaskAverage Cost (30m²)
Project management£4,000
Scaffolding£4,750
Internal preparation£7,000
Alterations to roof structure£5,000
Steelwork to support structural changes£6,000
Roof coverings£8,250
Electrics and plumbing£3,250
Joinery (excluding staircase)£4,500
Staircase£2,750
Plastering£2,750
Decoration£1,750
Total£50,000

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Cost of a loft conversion in a semi-detached house

For a loft conversion in a semi-detached house, you have a range of options to choose from. Although you can easily add a Velux or dormer loft conversion, a hip to gable loft conversion is the best option for achieving the most extra space.

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

Cost of a loft conversion in a detached house

In a detached house, you have the opportunity to combine several types of loft conversion to maximise space. By combining a hip to gable conversion with dormer room and Velux conversions, you can increase loft space considerably, allowing enough height for a new bedroom and a staircase leading up to it.

Although this type of expansion is costly, this investment will be returned in increased value to your property. The average cost of a loft conversion in a detached house is £62,500.

Cost of a bungalow loft conversion

Bungalows are well suited to a range of different loft conversions. This is because lofts in bungalows tend to be larger than the average house, so have space to expand internally through a Velux loft conversion, or to expand externally through a mansard or hip to gable loft conversion.

However, as bungalows can have a larger footprint than other types of houses, this means that a bungalow loft conversion can be more expensive. The average cost of a bungalow loft conversion is between £62,500 and £87,500.

Cost of flooring for a loft conversion

Whether you’re hiring a builder, or installing it yourself, flooring can make a massive difference to your loft conversion, creating a neat, sophisticated space. Here’s what you can expect to pay when choosing flooring for your loft conversion:

Type of FlooringAverage Cost per m²
Vinyl£15 to £25 per m²
Wood£20 to £85 per m²
Carpet£10 to £65 per m²
Tiled£50 to £100 per m²

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Cost of insulation for a loft conversion

It’s vital that your loft conversion is properly insulated against the elements. There are several different options when choosing insulation.

Sheet insulation comes in rigid sheets that you can fit into your loft in sections. It is one of the easiest forms of insulation to install and is a good option if you are choosing to do it yourself. For sheet insulation, you can expect to pay between £15 and £30 per m².

Loose-fill insulation consists of small particles of foam, fibre or other materials, and can be formed to fit any surfaces. Loose-fill insulation is slightly more effective than sheet insulation, as it doesn’t have seams, so it can fit into gaps and holes easily. For loose-fill insulation, you can expect to pay £7.50 to £15 per m².

Blanket insulation is made up of flexible fibres that can easily fit into spaces, making it more adaptable than sheet insulation. However, blanket insulation is less durable than other forms of installation, so will need replacing regularly. For blanket insulation, you can expect to pay £14 to £29 per m².

Type of InsulationCost per m²
Sheet Insulation£15 to £30 per m²
Loose-fill Insulation£7.50 to £15 per m²
Blanket Insulation£14 to £29 per m²

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Additional costs for loft conversions

When installing a loft conversion, the majority of your costs will be for labour and materials. However, depending on the specifics of your property and the type of loft conversion you’d like, you may need to pay extra.

If you think bats may be living in your loft space, you’ll need to hire someone to complete a bat survey. As all bat species are protected in the UK, proper surveys need to be undertaken to ensure that loft conversion work can begin. This will usually cost £400 to £750.

When completing a loft conversion, you’ll need to ensure the work is allowed according to Building Regulations. Having this approved can be a lengthy process, potentially delaying your loft conversion, and it will cost in the region of £500 to £1,250. To avoid this, you can hire a builder who is registered with the Competent Tradespersons Scheme. This allows tradespeople to prove their capability to work on projects, so you can avoid applying for approval according to Building Regulations.

Some loft conversions will require planning permission. This will usually be decided based on the scale of your conversion, and whether you’re in a conservation area. To submit a planning permission, you’ll usually pay around £462.

Often, lofts are used to store water tanks. If you need to move a water tank to make space for your conversion, this will cost you around £750. Depending on the state of your property’s exterior, you could incur extra costs related to cladding and rendering, which could cost between £2,000 and £4,000.

Although additional costs can be daunting, consulting with a professional tradesperson is one of the best ways to avoid going over budget or finding surprise costs along the way. It’s also worth considering the state of your property before you begin work, and any extra changes that need to be made before the work can start.

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How long does a loft conversion take?

A loft conversion is an exciting way to add space and transform the function of your home. However, the process can take a long time, so it’s worth preparing yourself for how long a conversion might take before you can use the space again. Below, we’ve created a summary of average times for different types of loft conversions.

Type of Loft ConversionAverage Time Taken
Velux loft conversionFour to six weeks
Dormer loft conversionFour to six weeks
Hip to gable loft conversionFour to six weeks
Mansard loft conversionEight to ten weeks
Modular loft conversionThree to four weeks
Shell loft conversionFour to five weeks
DIY partial loft conversionFour to five weeks

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How to reduce loft conversion costs

Want to add an extra room to your home on a budget? Below, we talk you through some of the ways to reduce loft conversion costs.

  • Hire a builder registered with the Competent Tradesperson Scheme – a huge cost that can be associated with loft conversions is having your plans approved according to Building Regulations. Depending on your conversion and local area, this can cost anywhere from £500 to £1,250. To avoid this cost, you can hire a loft conversion specialist who is registered with the Competent Tradesperson Scheme. Through MyBuilder’s tradesperson profiles, you can check each tradesperson’s qualifications and job experience before requesting quotes.
  • Explore cheaper, more gradual loft conversions – With a loft conversion, you have the benefit of scaling the work based on what you can afford. If you’re looking to complete a loft conversion on a budget, a shell loft conversion is a great option. You can ensure the conversion is structurally sound with the help of a registered tradesperson but can also save money by completing the project yourself.
  • Source materials and items yourself – A huge cost associated with loft conversions is materials. By shopping around and seeking out sales and deals, you could get your materials for a much lower cost, reducing your loft conversion costs overall.
  • Hire a reliable tradesperson – Although doing a loft conversion yourself can save you money, a faulty structure can be dangerous, and can set you back in the long run if built poorly. By hiring a reliable specialist, you can feel confident the job will be done correctly, so that you won’t be burdened with costs later on.
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Need to know

Although most loft conversions won’t require planning permission, your conversion will need to be inspected by the Building Regulations department in your local authority to make sure it is constructed accordingly. This is to ensure it complies with rules on fire safety, access, floor strength and so on. To submit the plans and have an on-site inspection, this will usually cost between around £400 and £800.

Depending on your property type, you might also need a party wall agreement. This will be necessary if you live in a terraced or semi-detached house. This will also require your neighbours to agree for the work to take place. This agreement states that you would be liable for any damage to their home that may occur during the conversion work. Depending on the complexity of the agreement, it can cost on average £850 to £1,500.

FAQ

Do I need planning permission for a loft conversion?

Most loft conversions are considered permitted development (not requiring planning permission), so long as they follow local terms and conditions. However, this can vary based on the scale of your conversion, and whether you home is in an area of conservation. If you have to apply for planning permission, you can expect to pay around £462. This will usually only be required for large-scale conversions, such as mansard or hip to gable loft conversions.

Can loft conversions add value to your house?

On average, a loft conversion can increase the value of your house by up to 20%. This is ideal if you plan on selling your home in the future.

Should I convert a loft myself?

Although doing a loft conversion yourself can save on labour costs, if you don’t have previous experience, then you risk a poorly built structure that could be dangerous to live in. The best thing to do is hire a reliable specialist local to you, who can advise on completing a loft conversion safely.

Your loft conversion checklist

  • Plan beforehand – When planning a loft conversion, make sure to consider the space you’re working with, and what you intend to use the space for. If your loft houses a water tank or other structural elements, this needs to be considered in your plans too.
  • Check what suits your situation – Depending on your property, different conversions will work best. Consider this when consulting with your local builder.
  • Choose registered, competent tradespeople with relevant experience, qualifications and accreditations – All loft conversions will need to be completed according to Building Regulations. By hiring a builder who is experienced in loft conversions, and is ideally registered with the Competent Tradesperson Scheme, you can avoid any concerns about your conversion not being up to standard.
  • Hire a professional – Many loft conversions will alter the structure of your house, so hiring a professional is the best way to ensure a structurally sound conversion. At MyBuilder, we can help you find experienced, qualified builders local to you.

Need to find a reliable builder for your loft conversion? MyBuilder can help. Simply create your free job post, and our website will help match you to reliable, qualified tradespeople in your area.