AdviceConversionsCost guidesLofts

How much does a new loft conversion cost?

The prices in this guide are accurate as of 2023*

Illustration of a row of houses with the costs to get different loft conversions built according to property type
Average cost of loft conversion by conversion type

Loft conversions are a great way of maximising the available space in your home. This means that if you can’t or don’t want to move home at the moment, but need the extra space, you can still upgrade your home with a loft conversion.

Loft conversions also increase the value of your home (sometimes by up to 20%), and often don’t require planning permission applications, because they tend to be covered by Permitted Development Rights (PDRs). You can check planning permission regulations for loft conversions here.

How much you end up spending on your new loft will depend on the type of conversion you’re interested in getting. The most common loft conversions, and their average costs are:

Type of loft conversionCost range
Velux£40,000 to £75,000
Dormer£55,500 to £118,400
Mansard£70,000 to £150,000
Hip to gable £60,350 to £134,000
Bungalow£40,000 to £100,000
Average cost of a loft conversion, according to loft conversion type

Bungalow loft conversions can be built using any of the above styles. 

Loft conversions can be used for all sorts of things, from an additional bedroom to a home office, or even a gym. What you do with your extra space is entirely up to you, giving you a huge amount of creative licence. 

Picture of a loft converted into a bathroom with a large window and wooden floors

Keep in mind that the prices in this guide include cost of labour and cost of materials. The prices include VAT.

Expect to pay more if you live in London and the South East, where cost of labour can rise by up to 20% on average. The size of your loft, and additional costs like underfloor heating, can also bring up the overall price.

This guide covers prices for all the different types of loft conversions, as well as what other additional costs might look like:

How much does an average loft conversion cost?

The average cost of a loft conversion is £90,000, with a lower range of £40,000 and an upper range of £150,000, depending on the size of your loft, and what type of loft conversion you are getting. Where you live in the UK will also affect costs.

Picture of a loft conversion being used as a lounge area with a sofa, TV, and skylight

There is so much you can do with your loft. Leaving your old boxes to collect dust can be a waste of space when you could turn it into a guest bedroom, or a playroom for children instead. The possibilities are endless, and all of them could add value to your home.

Conversions also allow you to create more space without taking it away from other areas of your home, like your garden, in the way that rear and wrap-around extensions do. Also, because your loft already has lots of important structural foundations, it actually costs less (per square metre) to convert an old loft into a new room, than to pay for another type of extension. 

If you have a loft full of ‘dead’ space, converting it is a great, cost-effective and value-adding way to improve your home.

Are you wondering what you should expect to pay for a loft conversion? 

On average, a loft conversion costs between £80,000 and £90,000, with a lower range of around £40,000 and an upper range of £150,000.

It will take between 6 and 12 weeks for your loft conversion to be built.

Did you know that, in many cases, a loft conversion can also make your home more eco-friendly and energy-efficient? This is due to the added insulation that is installed in the loft during the conversion. The cost of insulating your new loft is also covered in this guide.

How much does a velux loft conversion cost?

The average cost of a new, velux loft conversion is between £40,000 £75,000. The most expensive velux loft conversions can go up to £80,000 or even more, whilst on the lower end, one-window, small velux conversions can cost as little as £30,000. Size and number of windows affects price. 

Picture of a bedroom loft conversion with multiple Velux roof windows

Velux or roof light loft conversions are the simplest and least expensive, because they don’t involve structural changes to your roof. Instead, a skylight window is added (usually a velux window), as well as a new floor and staircase to access the loft area.

They’re the most affordable loft conversion, making them very popular with homeowners. They also don’t usually require planning permission, which makes them great for people living in conservation areas.

Because they don’t involve structural changes, velux conversions provide the least amount of added space, and are therefore mostly suited for properties that already have large lofts. If you have a large loft, or are looking to convert yours with a fairly tight budget, then a roof light conversion might be the ideal renovation for you.

Taking between 4 and 7 weeks to build, the average velux loft conversion costs between £40,000 and £75,000 to complete. However, how much you spend on your velux conversion will depend on the size of your loft and the specific requirements of your project, such as how many windows you want installed. For example:

A 50 m2 loft conversion with two velux windows and no dormer would cost you roughly £41,100. This quote includes loft insulation, the labour cost of installing a bathroom suite (but not bathroom materials), and all the necessary preliminary and demolition work, plumbing and electrics, and painting and decorating. Drawings and building control are not included.

On the other hand, to get a velux loft conversion that includes all the above, but is double the size (100 m2), would cost you roughly £73,250.

For a more accurate quote of how much you might spend on your loft conversion, speak to a skilled loft conversion specialist today.

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How much does a dormer loft conversion cost?

The average dormer loft conversion costs between £55,500 and £118,400.

Picture of a loft with a dormer and two windows

Suitable for homes with a sloped roof, a dormer conversion involves building a box-like structure with a flat roof that sticks out of your existing roof.

Because they can be built on most roofs, including semi-detached, detached, or terraced houses, they’re a popular way to add loft space and introduce more light into your home through additional windows. 

The great thing about a dormer loft conversion is that there are plenty of different styles of dormer windows for you to choose from, allowing you a high degree of creative licence when it does to the outside appearance of your home.

You could go with:

  • A gable fronted, or doghouse dormer loft extension
  • A hip roof dormer loft extension 
  • A shed roof dormer loft extension
  • A flat roof dormer loft extension
  • A mansard roof dormer loft extension
  • An L-shaped dormer loft extension

Not all of these will be suitable for your particular roof. The best thing to do is speak to a specialist, who can advise you on the best option for your home. Tell us about your project, and get some free quotes today.

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Dormer loft conversion prices, according to size and number of windows:

30 m2 dormer loft conversion with 1 window£55,500
65 m2 dormer loft conversion with 3 windows£83,000
100 m2 dormer loft conversion with 3 windows£118,400
Cost of a dormer loft conversion

The average cost of a dormer loft conversion is between £55,000 and £120,000. How much you spend will depend on what you’re looking to get. For instance, the above prices include all demolition and preliminary work, plumbing and electrics (including labour costs for a bathroom suite, but not bathroom materials) and all the necessary plastering and decorating. They do not include drawings and building control costs or wall and floor tiles/finishes.

Dormer loft conversions tend to take between 6 and 9 weeks to build.

How much is a mansard loft conversion?

On average, the cost of a new mansard roof conversion is between £100,000 and £110,000. On the lower end, a small mansard loft conversion could cost as little as £70,000, or even less, whilst the upper price bracket for a mansard roof extension is over £150,000.

Picture of a loft conversion with a swinging chair and sofa

If your priority is getting as much extra loft space as possible, then a mansard loft extension is your best option on this list, because it will give you the largest loft conversion. As a result, they tend to be the most expensive to build.

They usually get built on the rear of your property, with horizontal roofs that have an almost vertical back wall. As well as a standard mansard, you could also look into an L-shaped mansard, or a double loft mansard conversion.

The good news is that they increase the value of your property, and are visually attractive from the outside. You can choose what material to use on the outside of your mansard, from slate to timber to brick cladding.

Because of the structural changes involved in building a mansard loft extension, you will likely require planning permission to have one built. If you aren’t sure whether a mansard loft conversion is the right fit for you, get into contact with a skilled tradesperson who can help you decide.

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The average mansard loft conversion costs between £100,000 and £110,000. On the lower end, you could pay around £70,000, whilst more expensive projects can cost upwards of £150,000. How much you end up spending will depend on the specific requirements of your project, like how many windows you want installed, and whether you want a bathroom or kitchen fitted as well.

Out of all the conversion types, mansard loft conversions take the most time to build, with an average of 8 to 11 weeks to complete.

How much does a hip to gable loft conversion cost?

The average hip to gable loft conversion costs between £70,000 and £100,000. A smaller one-window dormer hip to gable conversion could cost you £60,350, whilst bigger projects, with multiple windows and a dormer could cost as much as £134,000, or even more. Your location will impact on cost of labour.

Picture of a hip-to-gable loft conversion being used as a living room with sofas and plants

Hip to gable loft conversions are built into homes with hipped roofs, and are suitable for a lot of semi-detached, detached, or end-of terrace homes. A hipped roof is a roof that has three, equally downward sloping sides. The loft is usually built by turning one of the sides of your roof into a gable roof, creating a (triangular-shaped) vertical end wall.

Though there are some exceptions to the rule, most hip to gable loft conversions do not require planning permission, as they fall under permitted development rights. For more information, you can access the Planning Portal website.

Hip to gable loft conversions will add a lot more space and natural light to your home. Due to structural changes required to the joists and roof of your home, they usually fall in a higher-end cost bracket, costing a little less than mansard conversions.

An average hip to gable loft conversion will cost you around £90,000, or between £60,000 and £135,000.

Hip to gable loft conversion prices, according to size and number of windows:

30 m2 hip to gable loft conversion with dormer and 1 window£60,350
50 m2 hip to gable loft conversion with dormer and 2 windows£71,700
65 m2 hip to gable loft conversion with dormer and 3 windows£96,450
100 m2 hip to gable loft conversion with dormer and 3 windows£134,000
Cost of a hip to gable loft conversion

Prices will vary, depending on the specific requirements of your project. The above prices include (bathroom installation, but not materials), demolition and preliminary work, all necessary plumbing, electrics, plastering and decorating, but not drawings and building control costs.

A hip to gable loft conversion usually takes between 6 and 9 weeks to complete.

Are you thinking of getting a loft conversion? Tell us about your project, and get some free quotes today.

FIND A LOFT CONVERSION SPECIALIST

How much does a bungalow loft conversion cost UK?

The average bungalow loft conversion costs between £40,000 and £100,000.

Picture of a bungalow loft conversion bedroom

It’s becoming increasingly popular for bungalow owners to add a loft conversion to their home. This is because they can nearly double the available space of a bungalow, essentially creating a second storey.

You might just be looking to add a room to your bungalow. Or you could get a dormer loft conversion, a hip to gable loft conversion, or a mansard loft conversion added onto your bungalow. 

The bigger the conversion, the more it will cost. Some bungalow conversions can reach upwards of £120,000. On average, you can expect to spend between £40,000 and £100,000, depending on size and the amount of windows you want installed.

Most bungalows do not require planning permission, as they’re considered permitted developments.

Do you need planning permission for a loft conversion?

Whether or not you will need planning permission for your loft conversion depends on whether your project follows permitted development rules or not.
Make sure you check the criteria, which can be found here.

How much does it cost to insulate a loft conversion?

Insulating your loft is a vital step in the loft conversion process, and one that will ensure you enhance the energy-saving features of your house.  

A quarter of heat is lost through the roof of an uninsulated home. You could save over £250 a year on energy bills by properly insulating your new loft conversion. 

How much you end up spending on insulation will depend on the type of insulation you get, and the size of your loft. It could cost you anywhere from £800 to £3,000.

Additional costs 

You may want to budget for a few other additional costs.

Building inspection costs

You will need building regulation approval for your loft conversion, to ensure that it is structurally sound and safe. A building control surveyor will carry out site inspections to ensure this. This tends to cost around £400 – £800.

Architectural plans cost

You won’t necessarily need architect plans in order to convert your loft, but it doesn’t hurt to have a clear idea of what the plan for your project will look like, to help ensure the project runs smoothly. An architect can also make sure you maximise the amount of available space.

The cost of this service ranges from around £500 to £2,000, depending on the scope of your project, who you decide to hire, and how detailed you want your plan to be. Architects tend to charge between 3% and 7% of the total build cost.

Structural engineer hiring cost

A structural engineer carries out site visits, cost calculations, and site drawings. They usually cost between £750 and £2,200.

If you aren’t sure whether or not you might need this service, get into contact with some skilled tradespeople, and gather a few quotes. Make sure you have a good idea of what is included in your package, so that you can budget effectively for your loft conversion.

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Electrical wiring moving cost

You may need to move the electrical wiring in your loft, especially if there is a risk that it will interfere with the insulation. You need to hire an electrician for this, which could cost around £150 – £350. 

Hire a skilled electrician to help move your wiring.

Underfloor heating 

You can choose between electric underfloor heating and wet (water) underfloor heating, the second of which is slightly more expensive.

Underfloor heating costs between £1,200 and £5,000, depending on the type of underfloor heating you want installed, and the size of the floor you want fitted.

How much does it cost to remove a water tank?

If your water tank is held in your loft, you will probably want to move it during your conversion. This service usually costs around £750. 

How can I save money on a loft conversion?

The best thing you can do to make sure you don’t waste your money is to hire the right tradespeople, who are skilled, and will do the job for a fair price. Hiring cheaper labour could eventually incur costs down the line due to repairs or even a whole new renovation. 

We can help you find the right tradespeople for your project, so tell us what you have in mind to get a free quote, today.

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Here are some handy tips to ensure your project doesn’t exceed your budget.

  1. Get multiple quotes – don’t settle for the first offer you get, but rather shop around for a few different quotes first, so you can get a good sense of how much a conversion could cost you. Also, don’t be tempted by the cheapest quote, as the package might simply be offering less, leading to additional costs later. Always check what is included in your quote.
  2. If you’re adding plumbing to your loft conversion, such as for a bathroom, try and make sure that plumbing is installed above or near existing plumbing elsewhere in your house, as this will make sure you don’t spend a lot of extra money on big, structural plumbing changes.
  3. Buy larger windows rather than more windows – if you want to maximise how much natural light is coming into your loft conversion, buy bigger windows rather than lots of smaller ones, as this will be cheaper.
  4. Stay away from bespoke – standard products (and standard sizing) is cheaper to purchase and have installed, helping you keep in control of your budget.
  5. Consider if there’s any decorating you can do yourself. Smaller, less intricate jobs can be DIY, such as painting walls, if you’re confident and don’t mind chancing a professional finish. This will cut the cost of hiring a painter. 

Conclusions 

Loft conversions are a great way to make the most of the unused space in your home, and often for a lot less money than an extension.

Be patient, take your time, and make sure everything is in place for a professional, top-quality conversion. The best way to do this is by doing your research, so that you can make sure you know what to expect when it comes to planning, and paying, for your loft conversion.

Keep in mind that the size of your oft, and where you live in the UK, are the biggest factors impacting on costs. Additional insulation and underfloor heating will also raise prices.

And always hire skilled professionals. Find a loft conversion specialist today.

FIND A LOFT CONVERSION SPECIALIST

*The Rated People cost guides are produced in collaboration with the quote-building platform PriceBuilder, and a range of tradespeople across the 30+ trades on our platform were consulted. Please note that the prices included are for guidance only – how much you end up spending will depend on the specific requirements of your project.

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