How Much Does a Loft Conversion Cost? The Guild Guide to Loft Conversions

Without first understanding the size and scale of the conversion project, it’s difficult to provide a definitive cost. However, the core factor that will affect the price of your loft conversion is the type you opt for. We’ve broken down the costs for each type of loft conversion to offer a basic guideline on what you can expect to pay.

How Loft Types Affect Pricing

There are a variety of different loft types, all of which come with their own unique benefits and price tags.

Loft conversion cost

Velux loft conversions

Velux loft conversions are one of the most popular loft conversion options because they’re affordable and easy to install.  Velux are framed windows that have many options including tilting, blinds, powered and more. They can be reversed for easy cleaning.

Velux loft conversion – average cost between £15,000 – £20,000

Dormer loft conversions/extensions

Dormer loft conversions are usually extensions that protrude from an existing sloping roof to add to the usable space. In essence, dormer conversions are ideal if you’re looking to utilise the unused space at the top of your property.

Dormer loft conversion – average cost between £30,000 – £60,000

Hip-to-gable loft conversions 

Hip-to-gable conversions look to extend your property by transforming your sloped roof into a vertical wall (this is known as a gable). It’s not uncommon for residential properties to combine hip-to-gable conversions with dormer conversions to maximise space.

Hip-to-gable loft conversion – average cost between £40,000 – £60,000

Mansard loft conversions 

These are the most expensive types of conversion build because it involves changing the shape of your roof. This type of conversion (typically) features a flat roof with the back of the wall sloping inwards (usually by 72 degrees).

Mansard roof loft conversion – average cost between £45,000 – £70,000

These prices should serve as an approximate guide to your initial loft conversion cost. Be aware that these prices may fluctuate depending on the size and scale of your project – small loft conversions are typically cheaper than large, complex renovations. 

Additional Costs to Consider 

Alongside the actual conversion, there are other costs you may want to factor in before you begin the build. These include:

Roof Considerations that Affect Loft Conversion Costs

Roof tiles

You will need to decide on the design of your loft conversion’s roof tiles to ensure you’re happy with their appearance. Additionally, some of your original tiles from your main property may have to be removed during the loft conversion process, so bear this in mind.

Roof repair costs

It’s likely that your roof will also need to have work done during the loft conversion process (as stated previously). Typically, it would cost you around £500 to have your roof tiles power washed. However, during your loft conversion process, use the scaffolding to your advantage and clean the slates yourself – this will be cheaper and faster. As well as cleaning the tiles, this is a great chance to do all external decorating. To reduce costs of painting windows and other external woodwork, which needs to done around every 7 years, consider redecorating these whilst the scaffolding is up.  You may also have the opportunity to clean the gutters while you’re up there.

Choosing your truss style

Two truss styles will be available to you; trusses and rafters. Trusses are the large triangular frames that don’t cross through the loft space, rafters run along the outer edge of the roof.

Internal Walls

If you’re considering splitting your loft space into two single rooms, then you’ll need an internal wall to split the room up. Stud walls are around £500 (not including labour). 


You may be considering the prospect of removing your old windows to make way for newer, thermally efficient models. Be aware that Dormer windows cost more than Velux due to how they’re made. On average, you can expect to pay around £4,000  £6,000 for Dormer windows and around £750 – £1,000 for Velux. 

Sorting Out Gas, Water and Electricity For Your Loft Conversion

Plumbing costs

Plumbing is essential for any loft conversion project. Generally speaking, the more plumbing you need, the more expensive it’ll be. Shop around for a good quote for a plumber to ensure you get the best price – this is something we can help with!

If you need to relocate your water tank

Another cost associated with plumbing is moving your water tank. If your water tank is located in your loft (most are), then you’ll need to move it. In most cases, this will mean you need to have a new boiler system fitted (if your tank is still in use). 

On average, it costs around £600 to move a water tank. To replace a tank with a combi boiler, prices vary from £2,800 to £3,500. 

Electrical Costs

Your new loft conversion, however basic it is will need running electricity. The more electricity you plan to run through it, the more sockets you’ll need. In most cases, electricians charge by the hour and you can expect to hire one out for anywhere between £40 – £90 per hour (take a look at our electricians).

Some electricians will also offer their own plans regarding the electrical work needed, these plans cost around £300 – £450 and is well worth the investment. However, if you have a truss-style roof, you can expect plans to cost more due to the complex nature of the roof. 

Need a Loft Conversion in the UK?

Find a Craftsman are dedicated to finding you reliable, trustworthy and experienced contractors who specialise in loft conversion builds. We can also help you compare tradesmen across any trade, from carpenters, builders and plasterers to plumbers and electricians, through to landscape designers, paving contractors, interior designers, bricklayers and flooring professionals.

If you’re looking for an affordable and reliable way to get your loft conversion completed in the UK, we have Master Craftsmen that carry out loft conversion all across the UK. Take a look at our loft conversions page to find a company near you.

Frequently Asked Questions

What if I’m living in a bungalow?

Bungalows are prime candidates for loft conversions, and you can expect to pay around £40,000 for a bungalow conversion.

What if I want a loft conversion in a terraced house?

In most cases, loft conversion for terraced houses are permitted – so long as the loft conversion meets the required criteria and isn’t a listed or protected building. There are a number of variables that you need to consider before going ahead with a terraced loft conversion. For more information, visit Gov’s building control regulations.

Can I get a partial loft conversion?

The quick answer to this is yes, it is possible to get a partial loft conversion. However, like with any loft conversion, a partial loft conversion must comply with all current building regulations. This includes all electrical, plumbing and structural regulations.

How much can a loft conversion add to my home?

The UK bank Nationwide claims that a property featuring a loft conversion or additional bedroom could add approximately 20% value to this house. This is an attractive prospect to those debating between a loft conversion and moving house – the loft conversion being the cheaper alternative while adding curb and property value.
It would be in your best interest to speak to an architect and even an estate agency to understand how adding a loft conversion to your property (big or small) could affect its overall price.