How much does a loft conversion cost?

A loft conversion is one of the best ways to add more space to your home without moving. Whether you need a new bedroom, a quiet office, or even a playroom for the kids, turning your loft into a liveable room can make a big difference.

But how much does a loft conversion cost? What kind of loft conversion is right for you? And how do people pay for them? This guide will explain it in clear, simple terms—so you’ll feel confident about your next steps.

What types of loft conversions are available?

Not all lofts are the same, and the type of conversion you choose will affect your space, budget, and whether you need planning permission.

Velux conversion

The Velux or rooflight conversion is usually the cheapest and easiest option. It keeps the shape of your roof but adds skylight-style windows to bring in light. Because it doesn’t change your roof structure, it often doesn’t need planning permission and is quicker to complete.

Dormer conversion

A dormer loft conversion is one of the most popular types. This adds a box-like extension to the roof, creating more headroom and floor space. Dormers work well for extra bedrooms or bathrooms, and they suit most UK homes.

Hip-to-gable conversion

A hip-to-gable loft conversion is ideal for semi-detached or end-of-terrace houses. It changes the sloped side of your roof (called the hip) to a straight wall (the gable). This gives you much more usable room inside.

L-shaped dormer conversion

For even more space, an L-shaped dormer combines two dormers at right angles, often over the rear of your home. This type is perfect if you want two rooms or a bigger en suite.

Mansard conversion

The mansard conversion is the most expensive and transformative. It involves changing the roof slope completely to create a nearly vertical wall. Mansards often require planning permission and are common in cities like London.

Modular conversion

Lastly, modular loft conversions are a modern option. The new space is built off-site and then fitted to your home. This speeds up the build but can cost more upfront.

How much does a loft conversion cost in the UK?

Prices vary depending on the type of conversion, where you live, and the materials you use.

If you’re just adding Velux windows to an existing loft space, the total cost might start at around £15,000, especially if no structural work is needed. A basic dormer conversion will usually cost between £30,000 and £60,000, depending on how big it is and whether you include extras like a bathroom.

Hip-to-gable conversions typically start at £40,000, while mansard conversions can easily go beyond £70,000, especially in areas like London.

Modular conversions, while quicker to install, can cost between £45,000 and £75,000, depending on your design and finish.

Of course, these are just average ranges. Some projects may be more affordable—or more expensive—based on your home’s layout, the builders you choose, and your taste in materials and finishes.

Why do loft conversion prices vary so much?

The main reason prices differ is because of the work involved and how your current home is built.

If you need to hire an architect or structural engineer, that can cost anywhere from £3,000 to £10,000. Loft conversion specialist like them help make sure your new space is safe and well-designed.

Structural changes, like adding new steel beams, floors, or staircases, add to the cost too. For example, a new staircase that fits neatly into your layout might cost more to install but will make the space feel part of your home.

Before any work begins, you may also need planning permission or building control approval, depending on the size and scope of your loft conversion. In some cases, you’ll need a Party Wall Agreement if your home shares walls with neighbours. These permissions can cost hundreds or even thousands of pounds, especially if surveys or legal work are needed.

Don’t forget the cost of labour and materials, which can be £14,000 to £35,000 or more. Finishing touches like a new en suite bathroom, lighting, and floor coverings all add up too.

Finally, experts recommend saving an extra 10 to 15% of your budget for surprises—like fixing old wiring, dealing with damp, or upgrading insulation.

Is a loft conversion worth it?

In many cases, yes. A loft conversion can add up to 25% to your home’s value, especially in high-demand areas.

It’s also a great way to gain new space without moving house. You avoid estate agent fees, stamp duty, and all the stress that comes with relocating.

When compared to building a rear extension or conservatory, a loft conversion is often cheaper per square metre and less disruptive. Most work can be done with minimal changes to the rest of your home. To explore more, read our guide on which home improvements can add to your home.

How can I pay for a loft conversion?

Saving over time

If you’re not in a rush, saving for a few years may be a good idea. It avoids interest payments—but most people find it hard to save such a large amount quickly.

Using an unsecured personal loan

This means borrowing money without putting your home at risk. It’s a good option for smaller conversions, like a Velux-style update. Most unsecured loans offer terms of one to seven years, but interest rates may be higher than secured loans. To learn more, read our guide on the difference between secured and unsecured loans.

Taking out a secured loan

This is a common option for larger projects. A secured loan uses your home as collateral, which means you could borrow more at a lower interest rate than unsecured loans. It’s important to remember that if you don’t keep up with payments, your home could be at risk—so you should only borrow what you can comfortably repay. To learn more, read our guide on the pros and cons of secured loans.

Remortgaging

If you’ve owned your home for a while and have built up equity, remortgaging might let you release extra funds at a competitive rate. Just be aware that remortgaging usually means changing your mortgage term, interest rate, or lender—so it’s worth getting advice first. To learn more, read our guide on the difference between secured loans and remortgaging.

Equity release

This option is generally aimed at homeowners aged 55 or over. It allows you to release money from your home without making monthly payments—but it does reduce the value of your estate in the long run. Always speak to a regulated adviser before choosing this path.

What are the steps to start your loft conversion project?

Decide what you want from your loft: Do you need an extra bedroom, a quiet place to work, or space for a teenager? The answer will help guide the design.
Get at least three quotes from trusted builders: Make sure each quote includes all parts of the job—structure, labour, materials, and finishes.
Check if you need planning permission or building control approval: If you live in a semi-detached or terraced home, you may also need a Party Wall Agreement with your neighbour.
Calculate your full budget: Don’t forget to include architect or engineer fees, bathrooms, fixtures, and a buffer for unexpected costs.

Speak to a finance provider

You can explore loan options and agree on a repayment plan with your lender.

Conclusion

A loft conversion is a brilliant way to unlock space in your home and add value to your property. Whether you choose a simple Velux update or a luxurious mansard suite, planning and securing the right funding makes all the difference.

If you're ready to get started, Central Trust can help. We offer secured home improvement loans tailored to suit your project and budget. Call us free on 0800 980 6273, or fill out our quick enquiry form and we’ll call you back when it suits you.

THINK CAREFULLY BEFORE SECURING OTHER DEBTS AGAINST YOUR HOME. IF YOU DO NOT KEEP UP REPAYMENTS ON A MORTGAGE OR ANY OTHER DEBT SECURED ON YOUR HOME, THE LENDER MAY REPOSSESS IT.