The costs in this guide are accurate as of 2022
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 conversion||Average cost|
|Velux||£20,000 to £25,000|
|Dormer||£40,000 to £55,000|
|Mansard||£45,000 to £60,000|
|Hip to gable||£45,000 to £55,000|
|Bungalow||£20,000 to £55,000|
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.
Keep in mind that the prices in this guide include cost of labour and cost of materials. The prices do not include VAT.
Expect to pay more if you live in London and the Southeast, 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 £40,000, with a lower range of £20,000 and an upper range of £60,000, 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.
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 around £40,000, with a lower range of around £20,000 and an upper range of £60,000.
However, in some instances, loft conversions can cost as little as £15,000 or as much as £75,000, all depending on size and style.
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.Close section ↑
How much does a velux loft conversion cost?
The average cost of a new, velux loft conversion is between £20,000 – £25,000. The most expensive velux loft conversions can go up to £50,000 or even more, whilst on the lower end, one-window, small velux conversions can cost as little as £15,000. Size and number of windows affects price.
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 £20,000 and £25,000 to complete. This includes materials and building costs (such as flooring, plastering, plumbing, electricity, and staircase fitting).
However, how much you spend on your velux conversion will depend on the size of your loft.
Velux loft conversion prices, according to size:
|One room + one window (30 m2)||£20,000|
|One large room or two small rooms + two windows (50 m2)||£20,000 to £25,000|
|Two rooms + two or more windows (65 m2)||£25,000 to £30,000|
|Two or more rooms with several windows (100 m2)||Upwards of £50,000|
Some velux loft conversions can cost as little as £15,000, say for lofts of around 20 m2, whilst larger projects could cost as much as £50,000 or even more, if multiple windows are being added to a very large loft.Close section ↑
How much does a dormer loft conversion cost?
The average dormer loft conversion costs between £40,000 and £55,000.
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.
Dormer loft conversion prices, according to size:
|One room + one dormer (30 m2)||£30,000 to £40,000|
|One large room or two small rooms + two dormers (50 m2)||£40,000 to £50,000|
|Two rooms + two dormers (65 m2)||£45,000 to £55,000|
|Two rooms and two or more dormers (100 m2)||Upwards of £60,000|
The average cost of a dormer loft conversion is between £40,000 and £55,000. On the lower end, you could spend around £28,000, whilst some dormer loft extensions can reach £70,000 for really large conversions with multiple dormers. These prices account for materials and cost of labour.
Dormer loft conversions tend to take between 6 and 9 weeks to build.Close section ↑
How much is a mansard loft conversion?
On average, the cost of a new mansard roof conversion is between £45,000 and £60,000. On the lower end, a small mansard loft conversion could cost as little as £35,000, or even less, whilst the upper price bracket for a mansard roof extension is over £70,000.
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.
The average mansard loft conversion costs between £45,000 and £60,000.
Mansard loft conversion prices, according to size:
|One room + one window (30 m2)||£35,000 to £50,000|
|One or two rooms + two windows (50 m2)||£45,000 to £50,000|
|Two rooms + two windows (65 m2)||£50,000 to £60,000|
|Two rooms + two or more windows (100 m2)||Upwards of £70,000|
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.Close section ↑
How much does a hip to gable loft conversion cost?
The average hip to gable loft conversion costs between £40,000 and £60,000. A smaller, one-window, one-room hip to gable conversion could cost you £35,000, whilst bigger, two room projects with multiple windows could cost as much as £60,000, or even more. Your location will impact costs.
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 £50,000, or between £45,000 and £55,000.
Hip to gable loft conversion prices, according to size:
|One room + one window (30 m2)||£35,000 to £45,000|
|One or two rooms + two windows (50 m2)||£40,000 to £50,000|
|Two rooms + two windows (65 m2)||£50,000 to £55,000|
|Two rooms + two or more windows (100 m2)||Upwards of £60,000|
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.
How much does a bungalow loft conversion cost UK?
The average bungalow loft conversion costs £45,000.
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.
These could cost you:
- Around £50,000 for a hip to gable conversion
- Around £55,000 for a mansard conversion
- Around £45,000 for a dormer conversion
- Around £20,000 for a new room in your loft
The bigger the conversion, the more it will cost. Some bungalow conversions can reach upwards of £70,000.
Most bungalows do not require planning permission, as they’re considered permitted developments.Close section ↑
How much does a loft conversion cost with ensuite?
A master bedroom with an ensuite, of around 30 m2, in a new dormer loft conversion with a roof light and new staircase could cost you around £45,000.
How much you spend on your ensuite loft conversion depends on the quality of materials.
On average, buying and installing each of these bathroom items will cost you:
|Bathroom Item||Average cost of buying and installing|
|New bathroom tiles||£500 – £2,500|
|New shower||£350 – £600|
|New bathtub||£300 – £450|
|New toilet||£300 – £350|
|New basin||Around £350|
|New taps (pair)||Around £150|
|New radiator||Around £400|
|Underfloor heating||Ranging from £600 – £1,850 for 10m2|
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 £300 to £3,500.Close section ↑
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.
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 – £250.
Hire a skilled electrician to help move your wiring.
You can choose between electric underfloor heating and wet (water) underfloor heating, the second of which is slightly more expensive.
If you do want to install underfloor heating then you will need to budget for roughly £1,000, or between £600 and £1,850, for a 10 m2 loft.
The costs for underfloor heating, per m2, are:
|Type of underfloor heating||How much will it cost?|
|Electric UDH retrofitted per m2||£60 – £85|
|Wet UDH retrofitted per m2||£135 – £185|
|Electric UDH in new build per m2||£50 – £75|
|Wet UDH in new build per m2||£120 – £135|
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.Close section ↑
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.
Here are some handy tips to ensure your project doesn’t exceed your budget.
- 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
- 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
- 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
- Stay away from bespoke – standard products (and standard sizing) is cheaper to purchase and have installed, helping you keep in control of your budget
- 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.
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.