If you’ve run out of floor space in your property and are longing for another room or two, often the best option is to build upwards, into the roof space.
This can be tricky, with a myriad of questions and possibilities which can make it hard to know where to even start when planning a job of this scale.
In this article, we’ll be covering how much a loft conversion costs, what affects the price of a loft conversion, how to save money when converting your loft, what a loft conversion involves and how to find and hire a builder to carry out your loft conversion.
If you want a conversion, but haven’t a clue where to start, keep reading to find out everything you need to know and the prices and timescales involved in each aspect.
How Much Does a Loft Conversion Cost?
A loft conversion typically costs between £21,000 to £44,000, but you could easily pay up to £63,000 if you want a particularly large extension.
The estimated cost of a loft conversion by type and time required
|Conversion Type||Estimated Cost||Time Required|
|Roof Light or Velux Conversion||£20,000 to £49,000||4 to 7 weeks depending on size|
|Dormer Conversion||£30,000 to £69,000||6 to 9 weeks depending on size|
|Hip-to-Gable||£40,000 to £70,000||6 to 9 weeks depending on size|
|Mansard||£45,000 to £75,000||8 to 11 weeks depending on size|
For a conversion including a roof light or Velux window, you can expect to pay between £20,000 to £49,000, with a time duration of between four to seven weeks.
A Dormer conversion will cost a little more, coming in at between £30,000 to £69,000, and taking slightly longer at between six to nine weeks.
For a hip-to-gable arrangement, this will be between £40,000 to £70,000, taking six to nine weeks to complete.
Finally, the grandest option comes from the Mansard option which can cost anywhere between £45,000 to £75,000, and take up to 11 weeks depending on the size.
The estimated cost of roof light and dormer conversions by the number of windows/dormers and size
|Number of Windows or Dormers||Size of Loft Conversion||Size of Loft Conversion|
|2 roof lights||5 metres x 4 metres||£20,000 to £24,000|
|2 roof lights||5 metres x 6 metres||£24,000 to £28,000|
|2 roof lights||8 metres x 12 metres||£40,000 to £45,000|
|4 roof lights||5 metres x 4 metres||£22,000 to £26,000|
|4 roof lights||5 metres x 6 metres||£26,000 to £30,000|
|4 roof lights||8 metres x 12 metres||£44,000 to £49,000|
|1 dormer + 1 roof light||5 metres x 4 metres||£30,000 to £34,000|
|1 dormer + 1 roof light||5 metres x 6 metres||£39,000 to £44,000|
|1 dormer + 1 roof light||8 metres x 12 metres||£55,000 to £62,000|
|2 dormers + 2 roof lights||5 metres x 6 metres||£43,000 to £48,000|
|2 dormers + 2 roof lights||8 metres x 12 metres||£62,000 to £69,000|
For two roof lights, and a loft conversion size of five metres by four metres, you can expect a cost of between £20,000 to £24,000. For a slightly larger space of five to six metres, this price will rise to £24,000 to £28,000, and for an eight by 12-metre space, this will cap at £40,000 to £45,000.
Four roof lights and a conversion space of five by four metres will set you back by £22,000 to £26,000, while the same amount of lights in a space of five by six metres will be between £26,000 to £30,000. For a larger space of eight by 12 metres, this will become £44,000 to £49,000.
Moving onto Dormers, for a five by four-metre space with one roof light, you can expect to be charged between £30,000 to £34,000, while a five by six-metre space will cost you between £39,000 to £44,000. For the larger space of eight by 12 metres, this cost will settle at between £55,000 to £62,000.
If you want to have two Dormers and two roof lights, you can expect to pay between £43,000 to £48,000 for a five by six-metre space, while an 8 by 12-metre space will be between £62,000 to £69,000.
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What Affects the Cost of a Loft Conversion?
The biggest factor affecting the cost of a lost conversion is what type of budget you have for the project.
You will also need to determine whether the space is suitable, your type of roof, and if you’re going to need to seek out planning permission.
Simply put, the larger the conversion you want, the more money it’ll cost you. Instead of doing a budget job that isn’t as big as you’d like in the first place, it’s more cost-effective in the long run to save up that bit longer to get the entire job done properly the first time round to remove the need for rebuilds further down the line.
There are a few styles to choose from when it comes to loft conversions, all with different prices to help you decide:
- Velux – usually the most affordable option, involving affixing one or two windows to the roof to introduce light. This can cost between £21,000 to £41,000.
- Dormer – a very commonly used loft conversion, the Dormer is a flat-roofed extension that typically has a window.
It’s common to have two of these on one roof. However, side dormers and L-shaped Dormers (an extension added to the rear of the Dormer) are also available.
In the case of the latter, it could result in up to four new rooms. The cost for Dormer conversions ranges from £31,000 to £58,000 for a standard Dormer and £40,000 to £60,000 for an L-shaped Dormer.
- Hip to Gable – either one or both of the end sloping parts of the roof are replaced with a gable wall, which will cost between £42,000 to £65,000
- Mansard – this type of extension is usually the most expensive. A Mansard extension involves replacing one side of the roof with a straight wall and flat roof.
Both sides could be extended, resulting in a whole new storey. The renovation is major and would involve planning permission, and cost between £45,000 to £75,000.
Understandably, the material you choose for your roof will affect the price you pay. To read up on different roof types and their associated costs, see our dedicated page on it here.
Windows and Glazing
Much like the roof material, the type of window or glazing you choose will impact the price you pay.
Choosing between double and triple glazed, or different types of window frames and materials can bump up or reduce costs – for full information, see our dedicated page on new window costs.
Purpose of the Room
Before building, you must have an idea of what the space will be used for as it’ll directly impact the planning and price you pay.
If you want the space as an extra bedroom or home office, you’ll at least need electrical outputs, so it’s another job to get an electrician involved to send cabling to the right locations.
Party Wall Agreement
Regrettably not as exciting as it sounds, the Party Wall Agreement can cost up to an additional £1,000 on top of your project fee.
You must let your neighbours know about any work you are to carry out on your home before it gets started. The party wall stands on the land of two or more owners and forms part of a building.
Depending on the extent of your conversion, you’ll most likely need scaffolding for labourers to reach the heights necessary to undertake the work.
Your property may also need additional structural support while the work is being completed, so this is usually an inescapable feature of conversion work.
Rubbish Removal and Skip Hire
There will be a lot of masonry debris, along with your existing roof to get rid of while the job is happening. This will likely require the assistance of a skip hire – which can quickly become expensive if it’s at your property longer than anticipated, or filled with restricted items.
If you’d like to know more about how much rubbish and waste clearance services cost, we have a guide for that!
Or, if you’re planning on hiring a skip, see our dedicated page instead.
How Can I Save Money When Converting My Loft?
Converting your loft is one of the more expensive home renovations, but there are some ways to cut costs down.
Buy Materials Early
Part of what escalates costs quickly is the urgency for which you need materials and tools. By purchasing savvily you can be sure to get hold of the items you need at preferable prices to you – and not have your hand forced by your labourer’s deadlines.
By making purchases during sales or percentage off days, you can save a considerable amount of money instead of buying items at full price. All you have to put up with is having a few fittings laying around your home before they’re ready to be used!
OK, it’s not the most glamorous option but if you’re up to the challenge, removing the debris and rubbish accumulated from the job yourself can be a way to cut down on excess rubbish removal costs – and in some instances, a skip hire.
Liaise with your contractors to see what’s possible, and propose what you’d be happy to do up front so they know what your intentions are.
Make Good Yourself
With a lot of upheavals comes a lot of new space to paint, lay carpets and generally finish to make it look neat again.
Instead of hiring the help of a painter or decorator, if you’re up to it, it’s a great idea to do this final step yourself. This way, you’re just paying for the cost of materials and not for the labour costs of anyone else.
Especially if you’re on a road where you have no available parking at your property and have to pay for a parking permit to let the trader park outside, you’ll be thankful to chop this expense out of your projections by finishing up and making good yourself.
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What Does a Loft Conversion Involve?
A loft conversion is one of the more complex home renovation jobs out there. Many labourers are involved in the process, all with different jobs and purposes.
Here are some of the people you can expect to be involved in your project from the beginning to the very end:
- Architect or Structural Engineer – you may want to enlist the help of an architect to draw up the plans of your conversion before getting in touch with a builder to bring your vision to life. This way, you can maximise the space you have and what you’re able to turn it into.
Architects usually charge a flat fee, which is typically three to seven per cent of the total build cost. Structural engineers can cost between £750 to £2,200 for loft conversions, including site visits, calculations and drawings.
- Builder – an essential part of the loft conversion, you’ll need at least one builder to construct the walls, and find out what work can or can’t be done. You’ll also need insulation and soundproofing.
- Glazier – they will decide what type of windows are best, as well as being on-hand to fit them for you.
- Electrician – the conversion will need lighting and sockets for electrical equipment.
When it comes to electricians, it’s best to make sure that the contractor is qualified and listed on the government’s Registered Competent Person Scheme, and that they’re able to give you a BS7671 test certificate once they’ve finished allowing you to pass Building Regulations.
- Heating Engineer – the heating engineer will decide the best place to put any radiators in your conversion. You’ll want to ensure the contractor is registered with APHE or similar before agreeing to any work with them.
- Plumber – if you’re planning to make the conversion an additional bedroom, you may want an en-suite installed, courtesy of the plumber.
- Joiner – you potentially may need new ceiling joists. You might also want to ask your joiner about storage solutions, as loft conversations can be awkward shapes and you’ll want to maximise the space available.
- Plasterer – to smoothen out the walls once everything behind the scenes has been finished off.
- Scaffolder – if you’re extensions is larger than most you will likely need temporary roof support.
- Painter – to add the finishing touches to the new space
To find out how much tradespeople and labourers are likely to charger for their services, make sure to read our guide.
How Do I Find and Hire a Builder?
The best way to find a builder for your loft conversion is first to look around you – has someone on your street recently had their loft done, and you like the look of it?
Asking to see the space and, if they’re willing, sharing the name of their contractor can be a great way to find someone reputable to work for you. Not only can you see the proof of their work in the flesh, but you’ll have a recent, up-to-date review of their work from someone you already know – and they’re unlikely to recommend someone that’s no good
When this isn’t possible, you can take your search online. But to save you hours of faffing and flicking between websites, using HouseholdQuotes can help to streamline your search into one query while keeping you on one website.
What’s more, comparing quotes on HouseholdQuotes can help you to save up to 40% off your project fee – which is a lot when it comes to loft conversion prices!
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Ensuring the Professional is the Right Fit
As with all home renovations, getting a quote in written format is one of the first major steps in ensuring you get a reputable contractor.
No matter how nice someone may be to your face, whatever you agree verbally is just that – verbal. There’s no way of refuting what someone did or didn’t agree to in those circumstances, so it’s always best to get anything written down to serve as a reference point for both parties.
If the contractor isn’t coming from a word-of-mouth recommendation, it’s best to find out their experience and see some proof of their previous work to make sure they’re a good match for what you’re looking for.
If your friend has recently had a conversion done by a particular trader, asking to see it in person can be a great way to get a tangible feel for the space and if their work is what you’re looking for.
Whenever this isn’t possible, asking the trader for photos or videos of their work is the next best thing, as you can see the proof of their work in reality (and not just what they’ve written about themselves on their website).
Finally, all contractors worth their salt will carry sufficient insurance to cover themselves and you and your home while they work. Asking to see proof of this isn’t a step too far – and if the trader refuses or bucks at you asking, it’s best to step away from that deal, as they could be rogue traders with little care for the outcome for you.
If your existing floor plan is just too small for your family, extending into the roof is a great way to free up some potentially underutilised space in your home.
Here’s our final checklist to make sure you’ve considered all you need to before you get started on this project:
- Scope out what’s right for you: get someone in to take a look at your loft space and make sure there’s enough clearance for a conversion in the first place to save a lot of time (and potential heartache)
- What type is best for you? You may be swayed by your building layout but if you have free reign to choose, you can go between a Velux, Dormer, Hip to Gable or Mansard conversion, each with its associated costs and conditions
- What do you want the room for? A bedroom, bathroom, or study? These conditions will need to be known before work starts to make sure sufficient cabling or pipework can reach the room
- Find a reputable trader using HousehodQuotes – which can also help to save you up to 40%, which is a considerable saving on such an expensive project
- Look forward to relaxing in your newly-created extra space!
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Frequently Asked Questions
Do I Need Planning Permission or Building Regs Approval for a Loft Conversion?
If your home is a listed building, as with everything else, you’ll need to inform the planning department of any intended alterations.
If your proposed loft conversion is higher than the original roof or is potentially going to affect the view for those nearby, (as in the case of the Mansard), then neighbours are informed by your local planning authority and given 21 days in which to object.
This can put an abrupt end to your planning dreams – so it’s always best to talk it out with your neighbours before committing to any plans to make sure they’re satisfied you’ve tried to work around their needs, too.
Can a Loft Conversion Increase the Value of My Home?
It’s extra square footage for the homeowner, and if the original house was quite pokey, it’ll be saving them the hassle and upheaval of having the conversion done themselves – so you’re saving them time and effort, which will be reflected in your house price.
Do I Have Enough Space for a Loft Conversion?
As a rule of thumb, you’ll need at least 2.2 metres from the bottom of the ridge timber to the top of the ceiling joist to make the space usable as a loft conversion. But if you’re in doubt, have someone come round to take a look at the space for you.
What’s the Cheapest Type of Loft Conversion?
These can cost anywhere from £20,000 to £49,000 depending on the size and number of windows you choose.
Is a Loft Conversion Cheaper Than an Extension?
To put things into perspective, a 30 square metre roof light conversion costs between £24,000 and £30,000 depending on the number of windows you choose.
Alternatively, a 30 square metre loft conversion with one dormer and one roof light costs between £39,000 and £44,000.
By comparison, a 30 square metre extension built on a budget costs between £30,000 and £48,000 (not including any finishes). Based on these estimates, a loft conversion could be the more affordable option depending on the size and style you choose.
Not only will the extra accommodation provide you and your family with more breathing space, but your home should also fetch a better price when you come to sell – around 20% more, in fact, according to the HomeOwners Association.
In other words, adding a loft conversion is a win-win – providing you get the renovation right from the start.
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