Loft Conversion Cost – How Much Should You be Paying?

Everything you need to know about loft conversion cost in one handy place – including labour costs, materials, time frames, and funding.

If you are looking to create more space in your home or add value to it, then getting a loft conversion is a great idea. You could turn your unused loft into another bedroom, bathroom, study, or a gym! Whatever you decide to do with your loft conversion, you can be rest assured that you will be adding about 20% onto the value of your home.

Cost of a Loft Conversion
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Here are the Benefits of a Loft Conversion

Creates more space in your home

On average, it costs about £10,000 to move home by the time you calculate all of the expenses. Expenses include the cost of selling your home, hiring a removal company, redecorating the new home as well as any other modifications such as a new bathroom or kitchen. You could put that £10,000 towards the cost of a new loft conversion and avoid having to find new schools for the children, a new job, and a new parking space.

Adds value to your home

Converting your loft is an investment that will pay off in the future. On average, a loft conversion will add between 15% – 20% on to the value of your home. Properties with loft conversions increase their value by about £37,000 on average according to the nationwide building society.

Great value for money

Converting your loft costs a lot less than building an extension or moving to another home. Once the unused roof space has been converted, you could recoup some of the money by renting the new room. There’s no need to wait until you sell your house to get a return on your investment.

Allows more natural light into your home

Loft conversions that have dormer windows or skylights allow a lot more natural light into the room. It is well known in the health industry that natural light elevates our mood and gives us much needed vitamin D, which we get from sunlight.

Many uses

Having your unused loft space converted into another room gives you a lot of different options to choose from. You could use that room as another bedroom; turn it into a gym, a cinema, or even an office. 

Loft Conversion Estimates

The first step you need to take before you even think about building is to get some estimates. Getting a free estimate from a loft conversion company will give you an idea of the costs involved. There are so many different factors to take into account. The type of loft conversion you require, the size of your property, and the method of construction of your existing roof have to be taken into consideration.

Loft Conversion Cost UK

The average cost of a loft conversion in the UK is £19,000 – £30,000. Attic conversion costs will depend on your property's location. An attic conversion in a 3 bed semi-detached house outside of London may cost £18,000, but if it was in London, the cost nearly doubles at about £32,000.

Loft Conversion Costs

Loft Conversion Prices

Type of Loft ConversionCost
A shell conversion£15,800
A small loft conversion with electrics & windows but no plumbing£19,600
An average cost of a loft conversion£19,500 – £30,000

How Long Does A Loft Conversion Take?

The average time it takes to complete a loft conversion is about 4 -7 weeks. The amount of time it takes to complete the job will depend upon what type of conversion you choose. A small loft conversion, for instance, could be completed within four weeks. A large conversion can take up to 2 months. 

How To Plan For A Loft Conversion

The best way to keep things running smoothly without a hiccup is to create a detailed plan. Creating a detailed plan makes you become aware of unforeseen expenses and allows you to add them to your budget. When you are planning your loft conversion, you need to consider the following:

  • Escape Routes – there has to be access to an escape route, whether that’s fire a large window, skylight, or open stairway.
  • Ventilation – adequate ventilation is required to prevent the buildup of mould within the room.
  • Loft stability – to ensure structural integrity, you may need to have the ceilings lowered if the loft is higher than 2.4 m (From the top apex down to the bottom joists).
  • Energy conservation – wasting valuable energy can be avoided by using the most up-to-date insulation materials for your loft conversion. You will want to use materials that stop heat from escaping your home during the winter.

Loft Conversion Cost Calculator

Several different factors will affect the cost of your loft conversion. The main two considerations you need to take into account are the side of your property and the type of loft conversion you choose.

Due to building regulations, the majority of lofts will require some structural work before they can be used as a habitable room. There are several different types of loft conversion to choose from; you can find them listed below.

Types of Loft Conversion

The four most popular types of loft conversion you will find in UK homes are the Roof light, Hip to Gable, Dormer, and Mansard. The flat roof dormer is the most popular in the UK.

Dormer Conversion

A dormer extension doesn’t usually require any structural changes to the existing roof, which is one of the reasons why this type of loft conversion is so popular. If you are standing outside looking towards a property with a dormer extension, you will see it protruding vertically from the slope of the existing roof.

Another reason for the dormer's popularity is its extra headroom, which creates a lot more internal space. The extra space in the loft area provides good ventilation with a good amount of lighting. The cost of a dormer loft conversion is less than other types of conversions, which is another good reason for its popularity.

If money is not an issue and you want to create a big visual impact on your property, then a dormer type conversion might not be what you are looking for. If you really want to make your property pop, then you might be interested in a gabled dormer.

A gabled dormer costs a lot more money, but after seeing one, you will know why. The gabled dormer has an L shape, and it wraps around the back and side of a property. The only downside to this type of loft conversion is the headroom is limited.

Loft Conversion

Hip to Gable Conversion

A hip to gable loft conversion is a good choice for all types of properties except for mid-terrace houses. The cost of a hip to gable loft conversion for a semi-detached house, detached, end of terrace, or bungalow would cost more than a dormer loft conversion.

The hip to Gable loft conversion consists of straightening the slanted end roof to make a vertical wall. Once complete, the type of conversion blends in nicely with your home. If your property is a 3 bed semi-detached, the conversion would look far better if your neighbour has the same conversion.

Turning the loft into a room: it’s not too difficult to turn your attic into a room as long as you have enough space. You need to have a distance of at least 2.2 m between the top of the ceiling joist and the bottom of the ridge timber.

As long as you have the minimum required height, all you need to do is reinforce the floor (if required), add a staircase, insulation, skylights finishing off by final fittings, and decorating.

Roof Light Conversion

A roof light loft conversion is the easiest and most affordable type of loft conversion. These types of loft conversion are quite basic. They only consist of reinforcing the attic floor and adding windows.

Once the floor has been reinforced, and the skylights are fitted on the roof, you can start using the loft space as another room. It is not likely that you will need planning permission. If you did need planning permission for a roof light loft conversion, it is the easiest to get approved.

Keep in mind that the one thing that may hinder approval for planning permission for a roof light attic conversion is the minimum required height of 2.25 m in the middle. Something else to keep in mind is the fact that you are not adding any extra space to your attic.

Mansard Loft Conversion

You will usually see a Mansard loft conversion on the back of terraced houses. Mansard loft conversions are more visually appealing than a dormer loft conversion and are particularly well suited to Victorian style terraced houses.

Mansard loft conversions consist of raising the party wall to the desired height. Of all the types of attic conversions, the Mansard loft conversion offers the most headroom. The downside to a Mansard loft conversion is they are more expensive, take longer to build and almost certainly require planning permission.

Loft Conversion For Bathrooms

One of the most popular reasons why people have their loft converted is to turn it into another bedroom that has an ensuite bathroom. If you are considering having a shower or a bathroom installed in your loft conversion, it will be a good idea to install it above your existing bathroom.

By installing a loft bathroom above your existing bathroom, you minimise the amount of pipework. You will be to tap into existing water supply and drainage.

An extractor fan for a bathroom installed in a loft is essential. An extractor fan will make sure that any condensation from the shower or bath is redirected outside instead of landing on the interior walls of the room and causing mould to grow. Installing an extractor fan in your loft conversion will also make sure that there is adequate ventilation in the room.

Whichever type of loft conversion you choose, remember to make sure that you have enough headroom. You will need the height to install a shower, sink, and toilet, but you may get away with placing the bathtub under the eaves (be careful to mind your head).

Trying to position a toilet directly above the existing soil stack might be difficult in some loft conversions. If the correct positioning cannot be achieved, then a good alternative is to install a macerator. A macerator system can be hidden behind a stud wall or positioned behind the toilet.

Solid waste passes through the macerators rotating blades. Solid waste is reduced in size, so it is small enough to pass through your normal pipework. Although installing a pumped macerator system is the cheapest option, it is also the noisiest.

It takes approximately 30 seconds after flushing the toilet for the macerator to reduce the size of solid waste. It's not recommended to put sanitary towels and toilet system that uses macerator. It will block the system and cause problems.

Low Roof and Trussed Roof Conversions

Properties that have minimal headroom in the attic because of a shallow pitched roof are the most difficult to convert. Upon first glance, an attic conversion can seem pretty straightforward.

It’s not until you take into account the rafter installation and floor reinforcement that you realise you have lost at least 300 mm of headroom. When there is insufficient headroom in the attic, the only real solution is to open up the roof and make it higher.

The easiest solution to make the roof higher is to have custom-made roof trusses built off-site that already have the windows and insulation in place. When the custom-made roof trusses are ready to be installed, a crane can pick it up from the ground and position it on your property.

Unfortunately, you will definitely have to apply for planning permission if you were to choose this option. If you live in a semi-detached or terraced property, it’s quite likely that your application won’t get approved.

Instead of making the roof higher to get more headroom, dropping the floor is a viable alternative. Having the floor lowered is a quicker, easier, and cheaper solution to acquiring more headroom in the attic.

By lowering the attic floor, you will be making the ceilings lower in the rooms below. Older properties tend to have higher ceilings, so lowering the attic floor in an older property won’t really affect the headroom in the rooms below.

If the rooms below have high ceilings, there shouldn’t be a problem fitting the new steel joists underneath the existing ceiling. When the new floor installation is complete, the old ceiling can be removed.

Once the old ceiling has gone, it will free up the much-needed extra headroom for the attic. Having the attic floor lowered will increase the costs of the attic conversion by roughly 10%.

However, it is much more affordable to have the floor lowered than taking off the roof and having a custom-built loft craned into place!

Lowering the floor 

Most of the houses that were built after 1960 will not have a typical rafter roof construction. Instead, the majority of roofs are the prefabricated trussed type. At one time, most loft conversion specialists would shy away from prefabricated roofs because they were regarded as being difficult to convert.

However, thanks to modern techniques, these type of roofs can be converted successfully. The most difficult part of the conversion is making sure that the opposing roof slopes are tied together and supported.

Before any of the old trusses could be cut, the new structure has to be in place. Depending on the condition of the existing timbers, they may need strengthening. Fixing new timbers alongside the old ones is the usual method to strengthen timbers, but some people use prefabricated sheets.

An experienced loft conversion specialist will be able to tell you whether it’s possible to have your loft converted or not.

Loft Conversion Cost UK
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Loft Conversion Cost

Convert loft into a room costs

The cost of converting a loft into a room can be anywhere between £15,000 and £20,000. The cost of converting an attic into a room in London would cost between £30,000 – £40,000.

Dormer loft conversion: the majority of attic conversions in the UK is the dormer conversion. The dormer is created by building out sections from the existing roof that have vertical walls. A dormer conversion is suitable for almost all types of homes.

Dormer loft conversion cost

The average cost of a dormer loft conversion is roughly £44,000. At the low end, expect to pay around £30,000. At the high-end expect to pay close to £60,000. As with all types of loft conversions, the cost will depend on the size of the property, materials and labour expenses, etc.

Bungalow loft conversion cost

Average bungalow loft conversion cost varies between £30,000 – £68,000. As long as the appropriate planning permission has been given the go-ahead, there should be no issue converting the attic of a bungalow. 

Mansard loft conversion cost

Of all the different types of attic conversions available, the Mansard conversion is the most expensive because of its complexity. Prices of a Mansard attic conversion start at about £45,000 and can go up to as much as £70,000. The average cost is approximately £57,000.

Hip to gable loft conversion cost

Due to the complexities of a hip to gable loft conversion, the prices start at about £41,000 and can go up to about £65,000. The average cost of a hip to gable loft conversion is about £53,000 in the UK.

Loft Conversion Prices UK

The average cost of a basic 20 m² loft conversion in the UK varies between £8700 – £11,000 for the basic style of conversions. Expect to pay anywhere between £20,000 – £25,000 for a deluxe conversion.

The cost of a basic loft conversion with an increased room size of 30 m² would be somewhere between £9800 and £12,500. Prices for 30 m² deluxe conversion would start at about £20,000 and can go up to as much as £27,000.

Location20m² basic20m² deluxe30m² standard
North of England£11,800£26,500£13,000
Northern Ireland£8,700£19,400£9,700
East Anglia£11,400£25,400£12,450
South West England£10,750£24,700£12,400
South East England£12,200£27,300£13,550

How To Find A Good Loft Conversion Company

If you are in the early stages of planning to have your loft converted, I'm sure you will be asking yourself many questions. Typical questions people ask themselves in the early stages are how much does a loft conversion cost?

Do I need planning permission for a loft conversion? Who do I contact about having my loft converted? If you have no idea where to start, I always recommend my readers to use this website.

All you have to do is answer a few questions about your plans, and before you know it, you will have some of the best tradespeople at your home to give you a free no obligation quote.

Attic Bedroom Conversion

Stages of a loft conversion

Below you will find the five stages of converting a loft. It's difficult for a builder to give a breakdown of costs for each stage of the project. A lot of builders do not offer a breakdown of costs for each stage because each stage comes together to form the finished project.

If you are having your loft converted, you may feel more comfortable paying the tradesmen after each stage of the conversion is complete.


Loft conversion plans costs 

The first step you should take towards having your loft converted is to have plans drawn up. You will need to contact an architect to discuss your project, and they will be able to provide you with a comprehensive plan.

I would highly recommend using this website to find a good architect near where you live. The architect's loft conversion plans will show you how the finished project will look once complete.

The plan will include all structural changes and all of the necessary calculations for the project. You should expect to pay around £1000 for architect's attic conversion plans.


Planning permission costs 

Planning permission is not required for most loft conversions. The reason why planning permission isn't necessary for most conversions is that they fall under permitted developments.

There are some instances where you will have to apply for planning permission. An example would be if your property is in a conservation area. The cost of applying for planning permission in the UK is £172.


Building regulation costs

Whether you had to apply for planning permission or not, your loft conversion will still have to be inspected by a building inspector to make sure the work is carried out in accordance with building regulations.

When a building inspector assesses the work, they are looking to make sure it complies with fire safety, floor strength, and access, etc. The cost to have a building inspector inspect your property and review your plans will vary between £400-£800.

If you live in a semi-detached or terraced property, you might have to apply for a party wall agreement. Unfortunately, your neighbours will have to agree to the party wall agreement if it is going to impact their property in any way.

In any damage is done to your neighbours property during the work, you will be liable for the costs of repairs and survey fees. A party wall agreement for a loft conversion could end up costing you thousands of pounds that you weren't expecting.


Loft building costs

Work can only begin on the loft conversion when the finished plans have been approved. After the approval process, scaffolding will be erected all around the property. Once the scaffolding is in place, the tradesmen can begin to work externally on converting the attic.

Internal access to the loft will be created, and the tradesmen will be able to get inside the attic and begin to strengthen the floor. Once the floor has been strengthened, the next step is to install the dormers and alter the roof. Velux windows would be installed during this part of the roof alterations.

Next on the list is fitting insulation and interior walls followed by a staircase or ladder and the windows. Once all that has been done, the plumbing and electrics will be installed, followed by the walls and ceiling being plastered. After the plastering is finished, the skirting boards will be fitted.

Finally, the plug sockets, toilet, and sink are installed, and the conversion is practically finished. The only thing left to do is paint the walls, ceiling and skirting boards, etc. The painting should only be done once the conversion has passed its final inspection. The majority of the budget is spent here.


Other Loft Conversion Costs

However you plan to use your new room is going to affect the final cost. For example, using the room as an office or a bedroom is going to cost a lot less than using it as a bedroom with an ensuite bathroom.

If a bathroom were to be installed in the new room, it would cost a lot more. You would have to buy a bathroom suite, build a separate room within loft space, install plumbing, and extra windows, etc.

The type of roof you have will also affect the cost of an attic conversion. It usually costs more to have a slate roof altered than it does for a roof with concrete roof tiles. Something else you will need to take into consideration is the age of your property.

If your home were built before the 1960s, you would need to find out whether your roof was constructed with wooden trusses or a frame. If the roof was built with trusses, it cannot support as much weight as a roof built with a frame. You do have the option of having the trusses reinforced or replaced, but it will add more costs to the project.

Loft Converted into a Bedroom
loft converted into a bedroom

DIY Loft Conversion

If you are thinking about converting your loft, you should know that the cost for a DIY loft conversion is about £28,000 on average. Every project is different, and the prices will depend on the materials used, the specifications, and size.

A DIY loft conversion isn’t something to be rushed. It would benefit you financially to take your time, research costs online, and compare prices. Keep a close eye on your budget once your project is underway.

If costs seem to be spiralling out of control, make changes to your plan so you can keep within your budget. You should set aside an emergency project fund just in case you come across any unexpected expenses.

A basic loft conversion might be suitable for some do it yourself enthusiasts who know their own capabilities. However, if you plan on having a more complicated attic conversion such as hip to gable loft conversion, Dormer loft conversion, or Mansard loft conversion, you really ought to go with a professional loft conversion company.

The worst thing any DIY enthusiast can do is rush into starting a new project without carrying out some proper research. If you enjoy DIY and you want to start your own DIY loft conversion, you have to make sure to carry out some careful planning.

Research the cost of materials and purchase them before you start the project. You need to know how much does a loft conversion cost, so you don’t go over your budget. Time spent researching the costs of materials for a loft conversion is time well spent, it will save you money.

I have created a table below to help you get an idea of how much the materials cost for converting your attic. I hope you find the information in the table below helpful, and hopefully, it will help you when you are planning your budget.

A Breakdown of Loft Conversion Materials Cost
Electrics: lightbulbs, plug sockets, wiring and fixturesprices
Structural: joists, beams and masonry (including doors, staircase and flooring)    £1,500 – £5000
Windows: double glazed windows and a Velux skylight£800 – £2,000
Combi Boiler: might need a new one if existing one needs replacing£600 – £3,000
Insulation: ply-board, boarding and plasterboard£500 – £800
Interior decoration materials: wallpaper, paint, furniture and storage cupboards£800 – £30,000
Bathroom suite: including shower unit, furniture, tiling, wash basin and all pipework£4,500 – £6,000

Warning – If you plan to do a loft conversion as a do it yourself project, and you have never carried out a loft conversion, please think very carefully before you start. Please don’t underestimate the enormous time and financial investment this project will take.

If you are not sure you have the right skills to handle this type of project, it will be a much better idea to contact a specialist loft conversion company. The best place to find a professional, local loft conversion company is here.

Loft Conversion Cost in London

The average cost of a loft conversion in London starts at around £12,600 for a small 20 m² loft conversion. A Deluxe loft conversion would cost a lot more coming in at around £28,000. Loft conversion prices are higher in London because of the high cost of living and the high cost of materials.

20m²  standard20m² deluxe30m² standard
Inside London£13,500£30,000£15,100
Outside of London£12,600£28,200£14,000

How to Fund Your Loft Conversion

If you are fortunate enough to have enough savings to pay for a loft conversion outright that you shouldn’t have a problem. However, the majority of people will need to find a way to fund the costs of a loft conversion. Getting funding for your loft conversion shouldn’t be difficult as long as you have enough capital in your property.

Many homeowners find that the easiest way to fund the cost of a loft conversion is to remortgage their homes. Your mortgage lender shouldn’t have a problem borrowing you the money because you are using that money to add more value to your home.

However, your mortgage lender will only allow you to remortgage your home if the loft conversion increases the value of your home. You will need to show your lender that the value of your home has increased since you last remortgaged.

If the value of your home has gone down, then it’s likely that your mortgage lender won’t allow you to remortgage the house unless they are sure the value of your home is going to increase in the near future.

Unfortunately, remortgaging your home to fund a loft conversion isn’t always that easy. A lot of mortgage lenders have a maximum age limit for remortgaging a property. They will want to know how you intend to pay back the remortgage payments, and you will have to prove that you have a stable income once you have stopped working.

How equity release could help

If you are an older homeowner (over 55), you could release some of the equity in your home to pay for a loft conversion. Equity release is unlocking some of the wealth that you already have in your property. Releasing equity to pay for the cost of a loft conversion is a popular way of funding the project, especially if remortgaging isn’t an option for you.

Bank Loan for a Loft Conversion

Different Types of Loans

Taking out a loan to pay for the cost of a loft conversion might be cheaper in the long term. Remortgaging might seem like the cheapest option in the short term because of the low monthly payments, but spread out over many years, you would be paying a lot more.

Banks tend to approve loans for home improvements a lot more than they would for a new car or luxury holiday. If you are thinking about applying for a loan for a loft conversion, don’t be afraid to tell your bank what you intend to do with the money.

Another option that might be available to you is to take out a secured loan. Secured loans usually have higher interest rates than a normal loan. However, if you are going to get a loan to pay for a loft conversion, then ultimately, the value of your home will increase over time and pay for itself.

Getting A Loan in The Current Climate

You may find it more difficult to get accepted for a loan during economically challenging times (such as the 2008 banker’s crash or the coronavirus of 2020). If the current economic situation has reduced the value of your home, then your lender might be more reluctant to allow you to remortgage your home until its value has increased.

If you find yourself in this situation, it might be a good idea to wait for a few years until the value of property starts to increase. Banks are a lot reluctant to give out loans during economic hardship, but if you can prove you have a steady income and can afford the monthly payments, you shouldn’t have a problem.

Frequently Asked Questions

Do loft conversions add value to a house?

Many banks and building societies have carried out surveys over the years to find out what are the best ways to add value to your property. The survey results showed that having a loft conversion can increase the value of a property by as much as 20%.

Do You need planning permission for a loft conversion?

Some loft conversions do not require planning permission because they are classed as a “permitted development.” You would need to make enquiries with the planning permission portal to see if your project falls under the permitted development category.

How long does a loft conversion take?

The time it takes to complete a loft conversion is usually anywhere between six and eight weeks. However, the complexity of the project will affect how long it takes to complete. Another factor that must be considered is the initial planning. If you do need planning permission and you need a party Wall agreement, these can take time to process.


The cost of a loft conversion can vary a lot depending on what type of loft conversion you choose. The cost of materials, the company you choose, your location, and your intended use will affect the final cost.

I would recommend that you seek out a good architect (which you can find here) and have plans drawn up. If you need planning permission, you can apply here.

If you would just like a FREE no obligation quotation for a loft conversion, I recommend you visit this website. (The prices are unbeatable)

Good Luck!

Jim Ardale – Roof Advisor