The average price on a hip to gable
loft conversion is £54,000
Pricing guides

How much does a hip to gable loft conversion cost?

The hip to gable loft conversion costs in this article are correct as of 2022

Hip to gable loft conversions can add a dramatic amount of space to your home, converting the dead space lost in the slope of your roof into new headroom and lots of practical possibilities.

The cost of a hip to gable loft conversion is typically set by three main factors:

  • The size of the property and the roof being converted
  • The quality and specification of the finish, for example, if you're adding a bathroom
  • Other work being done, for example, if you're constructing a hip to gable with rear dormer

Though they are only possible in certain properties, when done properly, hip to gable conversions can have a huge impact and are often worth investing in.

We spoke to the experienced loft conversion specialists at MyBuilder to find out what you need to know.

Hip to gable loft conversion cost calculator

The factor that has the biggest impact on the cost of a hip to gable loft conversion is the size of the overall loft and the level of finish you are looking for in the final product - rought estimates are below:

  Semi-detached Detached
Hip to gable cost £36,000 £55,000
Bathroom £2,000 £4,000
Rear dormer £4,000 £6,000
Total £42,000 £65,000


Doing a double hip to gable loft conversion will be more expensive than a single conversion, however, it will not double the price, as much of the work to carry out the double conversion will already be necessary for the single conversion.

Many people will choose to add in dormers as well when carrying out a hip to gable loft conversion, to maximise available space. A hip to gable loft conversion with rear dormer will be more expensive, but is worth considering.

As a whole, we estimate a rough cost of £42,000, going up to around £65,000, with an average of around £54,000, which prices generally highest in London and the south east.

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Stages of a hip to gable loft conversion

There are a number of stages involved in completing an hip-to-gable loft conversion - you can expect to encounter all of the following if you take on the project: 


Hip to gable loft conversion plans cost

Plans for your hip to gable loft conversion will need to be drawn up either by an architect, or by an architectural technician or surveyor.

These plans should take all of the structural alterations needed into account, and can cost in the region of £1,000 plus VAT.


Planning permission costs 

Most hip to gable loft conversions will not require planning permission as they are considered permitted developments.

However, depending on the scale of the work, and other factors, such as being in a conservation area, planning permission might be needed.

Applying for planning permission currently costs just over £200 in England. 


Building regulation costs 

Regardless of your planning status, your hip to gable loft conversion will have to be inspected by the building regulations department of your local authority to ensure it is being constructed in accordance with the rules, making sure it complies with things like fire safety, access, floor strength and so on.

Submitting the plans for inspection and having on-site inspections can cost between around £400 and £800.

Another potential cost, though not always needed, is a bat survey if you believe your loft may have bats - this can cost up to £400.

How to keep your hip to gable loft conversion costs down

The best piece of advice for keeping costs down is hiring experienced and reliable tradespeople.

At MyBuilder, we typically advocate hiring particular specialists for each role, however, with hip to gable loft conversions, there are a number of ways of hiring the necessary tradespeople.

You could hire an architect to plan and let them oversee the entire project, hiring a team of builders and other necessary trades, or hire a specialist loft conversion firm who will have a team with all the needed skills.

You can also project manage the work yourself, hiring different tradespeople for different elements of the build, but it will require a lot of attention to ensure each stage runs to schedule and does not cause delays.


Hip to gable loft conversion building costs

When work begins, the initial construction will be carried out externally, with the use of scaffolding and in some cases a roof cover to allow work to continue effectively even with bad weather.

At some point, access will be created into the loft from the interior and the floor will be strengthened, while the roof will be altered.

Interior walls will be then be fitted along with insulation, and features such as the staircase will be installed, followed by windows.

Electrics and plumbing will go in, before it is plastered and carpentry such as skirting boards are fitted.

Electrical sockets and elements like the WC and sink, if needed, are then added, before the final conversion is ready for final inspection, and decoration can then take place. This is where the bulk of the costs are spent.


Other hip to gable loft conversion costs

The standard of fixtures and fittings in the loft will have a large impact on the cost of the project - for example, if you are simply planning to use the space as a large bedroom, it will be cheaper than if you are putting a bathroom in the space, where you will need to purchase the suite, which can cost several thousand pounds.

Moving the property’s water tanks if needed, and altering the rest of the home’s plumbing system, will also add to the overall price.

A slate roof will usually cost more to alter than one with concrete roof tiles.

Another factor is whether the roof was built with a frame - often found in pre-1960s homes - or with wooden trusses, which are easier to construct but can take less weight.

Replacing or reinforcing the trusses can take more work and thus increase the costs.

How long does a Hip to gable loft conversion take?

Six to eight weeks is the typical length of time for a hip to gable roof conversion.

However, the planning stage can also take a considerable amount of time, especially if planning permission is required.

You will usually be able to stay in your home, without too much disruption, for the duration of the work.

MyBuilder Top Tip

Hip to gable loft conversions add a considerable amount of floor space as well as headroom, however it is worth remembering the impact that the new staircase will have on the space below.

The area where you add the new gable may be most appropriate for the staircase, but you need to decide if you are happy with the space that will be lost on the first floor to make room for it.

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