How much does a hip to gable loft conversion cost?

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Usually found on semi-detached and detached properties, a hip to gable loft conversion is where a ‘hipped’ end of a roof is changed to form a ‘gable’ end to maximise floor space and head height. As with any type of conversion or extension, it can be a great way to add value to your home, but what are the cost considerations? The average hip to gable loft conversion cost in the UK is between £45,000 and £60,000. We look at what’s involved in a hip to gable loft conversion. All prices are estimates that are accurate as of 2024.

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The cost of a hip to gable loft conversion in the UK varies on average between £45,000 and £60,000 depending on a few factors, including the quality of the finish and the size of the property. Here, we explore what you can expect to pay and where you might be able to save money.

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We'll cover the following topics in this pricing guide:Average hip to gable loft conversion costsHow long does a hip to gable loft conversion take?How to reduce hip to gable loft conversion costsFAQYour hip to gable loft conversion checklist

Average hip to gable loft conversion costs

A hip to gable loft conversion involves different stages and processes, from the initial building work through to installing windows, insulation and bathroom fixtures.

Our cost calculator provides some average costs for the various elements involved:

Hip to gable loft conversion jobAverage cost
Single hip to gable loft conversion on an average semi-detached property£35,000 to £45,000
Single hip to gable loft conversion on a large semi-detached property£50,000 to £60,000
Single hip to gable loft conversion on an average detached property£45,000 to £55,000
Double hip to gable loft conversion on a large, detached property£60,000 to £70,000
Staircase£1,800 to £2,500
Windows£250 to £400 each
Insulation£750 to £1,000
Flooring£500 to £800
Bathroom fittings£4,500 to £6,000
Scaffolding£4,000 to £5,000

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How much does hip to gable loft conversion labour cost?

A big project like a hip to gable loft conversion usually means working with several different tradespeople with particular skills, including loft conversion specialists, plumbers, electricians and decorators. You can usually expect to have around two or three people working on the project at any given time, depending on the extent of the work involved. We would always recommend using professionals to complete a hip to gable loft conversion labour cost, rather than attempting a DIY job, to make sure your loft conversion is safe and built to a high standard.

Here are some average labour costs for a hip to gable loft conversion. These are typically higher in London and the southeast.

ProfessionalRate
Builder£25 to £35 per hour or £160 to £300 per day
Plumber£35 to £45 per hour
Electrician£55 to £100 per hour
Plasterer£30 to £55 per hour
Tiler£25 to £40 per hour
Decorator£25 to £50 per hour

Cost of an architect

You may decide to work with an architect to draw up plans for your hip to gable loft conversion. While this is not essential, involving an architect at an early stage can help you to come up with a clear plan for the build, identify potential pitfalls and possible save money and time further down the line. They can also help you make the best use of the space available and complete any paperwork needed to secure permission for the conversion.

You can usually expect to pay between £750 and £1,500 to have an architect create plans for your hip to gable loft conversion.

Cost of a structural engineer

A structural engineer is responsible for making sure that any new building work is structurally safe and sound. They can provide your builders with calculations and drawings to ensure the proposed work is completed efficiently and to a safe standard. They can also assist you with applications for planning permission (if necessary) and Building Regulations.

On average, the cost of a consultation with a structural engineer for a hip to gable loft conversion is between £750 and £2,000.

Cost of Building Regulations

A hip to gable loft conversion needs to comply with Building Regulations, which stipulate the layout of the conversion, the use of certain materials and the type of staircase you have, among other factors. These regulations ensure that the work is structurally safe, and evidence of compliance is essential when you need to resell your home. Check that your loft conversion specialist has arranged any necessary inspection to ensure their work complies with these.

An inspection is usually carried out by a building control officer or your local authority. It typically costs between £500 and £900.

Note that if your builder is registered with the Competent Tradesperson scheme, they will already be deemed compliant, and you won’t need to apply to Building Regulations.

Cost of a bat survey

As unlikely as it might sound, if you suspect there are bats nesting in your roof, you’ll need to have a bat survey carried out. Bats are protected by UK law, so you might need a licence before the loft conversion work can go ahead. A bat survey generally costs about £400 to £700.

Cost of scaffolding

Before they can start work, your loft conversion specialist will need to arrange for scaffolding to be erected in order to gain access to your roof. The cost of scaffolding hire is typically between £800 and £900 per week, or around £4,000 to £5,000 for the duration of the work. Double check that this is included in the quote you receive from your builder.

Cost of loft insulation

Having a loft conversion done usually involves adding insulation to your roof, which will help to make your home more energy efficient. Many people choose to use blanket loft insulation, which is easy to install and affordable at around £20 per m². At the more expensive end, there’s sheet or foam board insulation, which costs approximately £30 per m².

Overall, the average cost to insulate a hip to gable loft is £750 to £1,000 including labour.

Cost of windows

Windows are usually installed around the second week of a hip to gable loft conversion, once the roof structure has been altered. The cost depends on how many windows you need and the style you choose.

The average cost of windows in a hip to gable loft conversion is between £250 and £400, excluding labour. Dormer windows usually cost more than roof (Velux) ones.

Cost of a staircase

Once the main structural work has taken place, your builders will install a staircase. This can cost anywhere between £1,800 and £2,500, plus the cost of labour.

Cost of flooring

Flooring is another cost consideration when you’re working out a budget for your hip to gable loft conversion. The most affordable option is vinyl flooring at between £15 and £25 per m². Carpet costs anywhere between £10 and £65 per m², and wooden floorboards typically cost £30 to £80 per m². If your loft conversion includes a bathroom and you want to tile the floor, you can expect to pay between £60 and £80 per m².

Cost of electrics

Installing lighting and electric sockets is a key part of any loft conversion. The average cost to install and test electrics in a hip to gable loft conversion is between £400 and £600, with an electrician typically charging between £55 and £100 per hour.

Cost of bathroom fittings

If you’re planning to use your hip to gable loft conversion for a bedroom, you may want to add a bathroom too. Installing a new bathroom suite, including a shower, toilet and sink, typically costs between £4,500 and £6,000.

Cost of internal walls

If you plan to split your new loft space into more than one room, you will need to factor in the cost of adding an internal stud wall. You can typically expect to pay between £750 and £1,000 for the wall itself, plus plastering.

Cost of built-in storage

You can make the most of your new space with built-in storage like wardrobes, cupboards and shelves. Depending on the spec and size of the storage you want, you should usually budget between £2,500 and £5,000 for this.

Cost of decorating materials

Decorating your new hip to gable loft conversion includes laying carpet, fitting skirting boards, plastering and painting or papering walls. The cost of decorating materials for a hip to gable loft conversion is between £800 and £1,000 on average. This doesn’t include the cost of labour, which is usually charged at between £25 and £50 per hour.

How long does a hip to gable loft conversion take?

A hip to gable loft conversion should take around eight to ten weeks on average, assuming the necessary tradespeople are available at the relevant stage of the project. Any delays during the earlier stages can have a knock-on effect on the overall timeline.

Here are some of the average timeframes involved in a hip to gable loft conversion:

JobTime
Putting up scaffoldingOne day
Structural changes to roofOne to two weeks
Fitting windowsOne day
Installing staircaseTwo to three days
Fitting bathroomFour to five days
ElectricsTwo to three days
Fitting flooringOne day
Decorating and finishingThree to four days
Taking down scaffoldingOne day

How to reduce hip to gable loft conversion costs

Major building work like a hip to gable loft conversion usually involves a significant outlay, and you may be looking for ways to save money. Working with an experienced and reputable loft conversion specialist is the best way to ensure your project stays within budget and runs to time, but there are some other practical ways you can save money on your hip to gable loft conversion:

  • Get a few quotes to compare – Whether you’re looking for a builder, a structural engineer, an architect or an electrician, it’s worth requesting more than one quote so that you can be confident you’re getting a competitive price. MyBuilder’s extensive network of tradespeople in your area means you can request several quotes for comparison and choose the one that fits your budget.
  • Reuse or recycle materials – Consider ways of upcycling existing furniture or using second-hand materials like reclaimed wood for flooring. This can reduce waste and save you money. Bear in mind that any reclaimed materials should meet safety standards, so always check with your loft conversion specialist first.
  • Hire loft conversion specialists registered with the Competent Tradesperson scheme – The Competent Tradesperson scheme is a government-backed initiative that requires tradespeople to self-certify that their work complies with Building Regulations. Working with a builder who’s registered with the scheme means you won’t need to apply for Building Regulations approval.
  • Hone your DIY skills – If you feel confident, you might decide to complete the finishing touches to your hip to gable loft conversion yourself to save on decorating costs. DIY jobs might include wallpapering, painting, tiling or laying carpet.
  • Choose a basic finish – While appealing, luxury finishes and fixtures can have a big impact on your overall budget. If you want to save money, you could instead choose more basic bathroom fixtures, lighting and finishes. You can always upgrade these over time as and when your budget allows.
     

FAQ

What is a hip to gable loft conversion?

A gable roof consists of two sloping sides, whereas a hip roof has four. A hip to gable loft conversion straightens an inwardly slanted roof at one end of a house to create a vertical wall.  This effectively changes a hip end into a gable end, adding both floor space and head height. Homeowners often add a rear dormer to maximise this additional space.

A double hip to gable loft extension is where both ends of a detached house are converted from hips to gables.

A hip to gable loft extension is ideal for end-of-terrace, semi-detached and detached houses that have one or both ends exposed. They are not possible on mid-terrace houses.

Do I need planning permission for a hip to gable loft conversion?

Most hip to gable loft conversions count as ‘permitted development’ and don't require planning permission.

However, if you live in a conservation area or your building is listed, it is likely that you will need to apply for permission before making any structural changes.

You should also apply for a lawful development certificate from your local planning authority, which confirms that the build was legal at the point of construction.

Will a hip to gable loft conversion add value to my home?

House prices can be unpredictable, and there is no guarantee that a hip to gable loft conversion will add overall value to your home. However, there is some evidence to suggest that an average-sized loft conversion on a three-bedroom house can add about 20% to its value.

It’s also worth factoring in the added value to your life. If your family is growing or you need more space for work or hobbies, building a hip to gable loft conversion can enable you to accommodate those needs without the expense of moving house.

It’s important to ensure the conversion is completed to a high standard and complies with Building Regulations so that there are no issues that come up on a survey when it comes to reselling.

Your hip to gable loft conversion checklist

 
  • Explore the options: Whether you choose a single or double hip to gable loft conversion, or one with an additional dormer, depends on your budget and the style and size of your home. If you’re unsure, speak to a loft conversion specialist or architect for advice.
  • Get a range of quotes: Shop around to ensure you’re getting a quote that’s fair and competitive. When you post your job on MyBuilder, we’ll alert hundreds of relevant loft conversion specialists in your area so you can request a few quotes for comparison. 
  • Include a buffer: Build a buffer into your budget in case any additional costs crop up.
  • Find a loft conversion specialist you trust: Working with experienced, reputable builders is key to ensuring your project stays within budget. MyBuilder carefully checks out the work histories and accreditations of all applicants to our network so you can be confident in finding a loft conversion specialist who has the relevant skills and experience.
  • Don’t forget the hidden extras: Your overall budget for your loft conversion should include the cost of any plans, reports, inspections and applications, as well as other extras like scaffolding and skip hire. 
  • Apply for the relevant permission: Your builder will need to apply to Building Regulations to ensure their work is compliant, and if your home is listed or you live in a conservation area, you might need planning permission too. Ask your loft conversion specialist for advice on the types of consent you need.
  • Think about the weather: Planning loft conversion work for the summer means it’s likely to be drier and lighter, so work can proceed without interruption. It’s worth making enquiries and booking in a date as early as possible.

    Planning a hip to gable loft conversion and want to find a reliable loft conversion specialist near you? It’s completely free to post your job on MyBuilder, and we’ll share it with hundreds of trustworthy, qualified builders in your area. You can read reviews from other customers, check out tradespeople’s experience and reach out to anyone who looks suitable.