Planning your roof lantern installation project

Roof lanterns are a brilliant way to let sunshine into your space – especially if parts of your home are feeling a little dingy.

However, these beautiful glazed features do need careful planning.

We guide you through the process including planning and building regulations, how to approach the project, the costs involved, and FAQs.

Planning your roof lantern

Roof lanterns will create a statement feature in any room. They will also let masses of natural light pour into your home.

You can install a roof lantern as part of a new extension – or retrofit one into an existing space. Either way, good planning and research is crucial to a successful roof lantern installation.

Roof lanterns alter the structure of your roof and impact on the structure of your property, so planning and installation needs to be carefully considered.

In this planning guide, we outline what’s involved in a roof lantern installation, the rules and regulations that you need to adhere to, FAQs, and the costs involved.

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What’s involved in a roof lantern installation?

Roof lanterns are complex projects which need to be structurally sound. Work with a recommended builder or roofer who has experience of installing roof lanterns in a number of different properties.

Many roof lanterns are bespoke creations manufactured to a specific size and specific dimensions. So getting hold of your new roof lantern might take a couple of weeks.

Once it’s delivered, installation, however, should only take two to three days in total.

Here’s a basic checklist to planning your roof lantern installation. 

Step 1

Hire a structural engineer. A structural engineer will come to your house and create a plan of action and make sure the roof lantern position and overall structure will be safe.

Step 2

Your builder, carpenter or roofer will form an opening in the roof during the carcasing process. The manufacturers of the roof lantern should supply details of the sizing and if upstands are needed. There should also be advice on insulation to avoid cold bridging and condensation.

Step 3

There might be a delay between the roof being formed and the roof lantern being delivered and installed. A temporary cover needs to be put in place – corrugated plastic sheets will do the job really well.

Step 4

Roof covering material is installed over the upstand before the roof window. Window flashings are fitted onto the upstand to ensure everything is waterproof.

Step 5

A local building control officer will inspect the work once the installation is complete. If it is deemed satisfactory, you will be issued a completion certificate.

Step 6

With your beautiful new roof lantern now installed, enjoy your light-filled space. It will be the centrepiece of your home!

Do you need planning permission?

Before you set your heart on a beautiful roof lantern, do you need to have planning permission?

You need to be aware of any potential planning permission rules surrounding roof lanterns. This will vary depending on where you live, so it’s a good idea to contact your local planning department at the very start of a project.

We would always advise seeking out the expertise of a professional who has experience of planning and installing roof lanterns. They have the knowledge to guide you through the process from beginning to end.

Here’s a brief round-up of planning rules and regulations for roof lanterns – but do contact a professional for expert guidance.

• If your new roof lantern is higher than an existing roofline you may well need to seek planning permission. Remember lots of roof lanterns are installed in a flat roof, so will add extra height.
• If you can proceed under permitted development rights – and the roof lantern is no more than 4m from ground level – full planning permission may not be needed.
• If you are installing a roof lantern as part of a new build or as part of an extension, you won’t usually need any consents.
• Flats, maisonettes and converted houses fall under different planning rules so do be aware of these.
• Stricter rules and regulations come into force if you live in a conservation area or an Area of Outstanding Natural Beauty – so do check with your local authority or conservation officer.

What about building regulations?

Whether your roof lantern project needs planning permission or not, there are a number of building regulations that will apply. These need to be passed and inspected by building control to ensure your roof lantern is safe.

Roof lanterns are complex projects which need to be structurally sound. You’ll need to consult a structural engineer before installation.

Read our structural engineer cost guide to give you an idea on price.

If your roof lantern is being installed into a new extension or new build property, then the building regulations can be dealt with all at once as part of a bigger project.

Consult a professional such as a window and joinery expert. This will take the headache and stress out of building regulations. Many companies will take on the responsibility of putting consent applications together and submitting plans to the local authority to view.

Here’s brief round-up of building regulations to consider.

1. Structurally sound: roof joists or rafters are likely to be rearranged and the roof needs to be able to support its own weight and the weight of the new lantern.
2. Energy efficiency: Part L of the building regulations requires roof lanterns to have good thermal performance and not lose excessive heat. This demands double glazing – at least.
3. Weatherproof: Edges need to be sealed properly usually with lead flashing. Roof lanterns need to withstand severe weather conditions.
4. Ventilation: Roof lanterns need to offer good ventilation for the room below. Check yours has sufficient air vents built-in.

How much do roof lanterns cost?

The average roof lantern installation cost in the UK ranges from £3,600 – £9,000.

The price you pay for installing your roof lantern will depend on a number of factors, including the specific size, shape and style of the roof lantern.

For accurate prices, we recommend speaking to your local roof lantern specialists to get detailed quotes for your area.

We have a comprehensive price guide to installing a roof lantern here. This covers additional costs such as scaffolding hire, labour costs and timescales which you need to bear in mind before taking the plunge.

Additional costs for roof lantern installation

When planning your budget for installing your roof lantern, it’s worth considering extra costs that you might need to cover.

The condition of your roof: if there are any issues with existing roof damage you will need to get it fixed before or at the same time as fitting the roof lantern.

Part of an extension: the cost of your roof lantern should be built into the total cost of the extension project. For more details on the price of an extension, take a look at our house extension cost guide.

Automatic openers: Due to its elevated position, it can be difficult to open a roof lantern manually. If your roof lantern does have windows that open, add automatic openers.

Trickle vents: These will ensure sufficient ventilation in the room – something that’s needed to comply with British building regulations.

Scaffolding hire: Some roof lantern specialists will supply their own scaffolding to carry out the work, but others might need you to organise it for them.You can find out more about prices in our scaffolding cost guide.

Size and shape of roof lantern: The bigger the roof lantern the more expensive it will be – both in materials and labour costs. Expect to pay more for more complex shapes and a bespoke design.

Frame material: uPVC is the cheapest option on the market, aluminium frames are a mid-way price. Timber frames are the most expensive.

Type of glass: Tinted, toughened and self-cleaning glass options are all available and should be discussed with your local roof lantern experts at the beginning of the project. Double or triple glazing will also cost a lot more than single glazed glass.

FAQs

What is a roof lantern?

These elegant overhead glazed structures are made up of separate panes of framed glass, extending the roof upwards into a sort of mini conservatory.

Roof lanterns are different to rooflights which are simply flat windows set into a pitched or flat roof. Roof lanterns elevate a room, heightening the dimensions of your space to create a light and airy mood with a 3D glazed structure.

You might find an original roof lantern in period properties as they were first introduced in the Victorian era as ornate architectural features.

Today, roof lanterns are popular features in both modern and traditional homes – and can become a focal point for every style of property.

Beautiful and practical, they can be fitted to both flat or pitched roofs, and lay flat to the roofline or raised above it.

What is the difference between a roof lantern and a skylight?

The terms roof lantern and skylight are often used interchangeably – both meaning a glass window installed into a roof.

Depending on the manufacturer or tradesperson, they may use one or other of the terms to mean the same thing.

Where should I put a roof lantern?

Roof lanterns work really well in flat roofs and are a good choice if you’re planning to build a new single-storey extension. The 3D glazed structure will completely change the look and feel of a room.

Kitchens and dining areas are favourite spots for installing roof lanterns. Position over a dining table or island unit and let the light flood across your cooking and eating zones.

Any large open plan spaces in need of an extra burst of sunshine will also benefit from the brightening benefits of a roof lantern. Choose a central position so the light can flood into the communal, most well-used areas of a room.

These are really gorgeous additions to a home – but do need to be well planned before installation.

Can you fit a roof lantern yourself?

If you’re an experienced and skilled DIY enthusiast then you may be able to install a roof lantern yourself, but we would highly recommend hiring a professional to do the work. A poorly installed roof lantern could cause a whole heap of problems down the line so hire an installation expert, ideally a tradesperson who is registered with FENSA.