Skylights and rooflights – everything you need to know

With lots of us looking to extend and improve instead of moving, the popularity of renovations such as adding skylights and rooflights is on the up.

’Whatever you like to call them – roof window, skylight or rooflight – they all serve the same purpose, which is to bring natural daylight into your home,’ explains David Mayo, Managing Director of Sterlingbuild. ‘They bring in a substantial amount of light to a room all year round. Which in turn can give that area a feeling of being bright and airy.’

As with most renovation projects, the planning and installation process of installing skylights naturally brings up a whole load of questions. While they might offer more light in a room, do they also make it colder in winter? And what about direct sunlight and heat in the summer months? And what’s involved if you decide to install one in your home?

Skylights and rooflights – the lowdown

We explain the nitty gritty when it comes to installing skylights to your home. From the costs involved, to the intricacies of planning permission and all the confusion that might entail. Our guide will take you through everything you need to know (and the things to avoid) when bringing some extra light into your home.

What is a skylight?

‘A skylight is essentially a window, located in the roof, that brings daylight, into a room,' says Natalie Goodridge, Marketing Manager at Lamilux. ‘They're a popular design choice for residential new builds and extensions with limited natural daylight. They can also offer the added benefit of supplying a room with fresh air through opting for an opening skylight for ventilation.’

However, not all rooflights are the same and there are some key differences worth considering.

• Skylight/rooflight Both terms refer to a window, located in the roof
• Roof window A roof window is as it sounds – essentially a pane, or panes, of glass installed into a flat or pitched roof.
• Roof lanterns These have the appearance of small conservatories - they can be fitted to a flat or pitched roof.

Whether you’re installing a roof window, a skylight or a roof lantern there are various options available. These can allow for ventilation or limiting the amount of light which enters your room.

Where should I position my skylight?

Where you position your skylight or roof window is an important decision. Skylights and roof windows let in daylight all day. But, depending on the direction your house and room is facing, you’ll get more concentrated brightness at different times of the day.

‘One of the first things to consider is where you would like the light to come in and what effect you’re looking to create,’says Scott Leeder, Marketing Director at Velux. ‘You should start by looking at the direction of the windows and the sun. Think about where and at what time of the day, you will need the most daylight in a particular room.’

‘You might be considering installing a roof window in a new flat roof kitchen extension,' says Scott. 'You'd like plenty of natural light to flood the space whilst the family enjoy breakfast together each morning. Then you should consider the orientation of the building and where to put the roof window to make this vision a reality.’

What are the skylight pros and cons?

The advantage of having more light in a room might seem obvious. But there are plenty of other benefits to installing a skylight. Natalie from Lamilux agrees. ‘Skylights can provide homes with a pleasant indoor climate thanks to maximising natural daylight and optional natural ventilation,’ she says. ‘Scientific research demonstrates health and wellbeing, and productivity benefits, can be linked to good indoor air quality.’

Pros of skylights

The main advantage of skylights are:

• Access to natural light. They let in more light than windows. Some research shows up to 40% more exposure to natural light. Sunlight can play a great role in lifting our spirits and making us feel happier. Natural light helps to keep our ‘circadian rhythms’ in check, which helps to regulate healthy sleep patterns.
• Better air quality. Skylights can provide homes with a pleasant indoor climate. This is thanks to maximising natural daylight and optional natural ventilation. Scientific research demonstrates health and well-being, and productivity benefits, can be linked to good indoor air quality.
• The feeling of space. The addition of a skylight introduces more light into a space, which in turn, can make your room look and feel bigger.
• Saving on energy costs. More natural light means less reliance on artificial, electric lighting. Sunlight can also help heat up a room. Cross ventilation from skylights and roof windows that open can also help cool them down. They have an air conditioning effect - both potentially cutting down your energy bills.
• Adding resale value to your home. It goes without saying but an attractive, bright and airy space is enticing to home buyers.
• Health benefits. Natural sunlight is a great source of Vitamin D, which is vital for maintaining a healthy metabolism, bones and muscles.

Skylight cons

There are, however, some potential drawbacks that are worth considering. Installing skylights can add to the length of a building project. This includes the ordering and delivery of the units themselves and then organising of installation. If not planned for and installed properly, you may find yourself facing problems.

The cons of installing skylights can include:

• Too much light. Knowing what a room will normally be used for might have a bearing on the positioning of a skylight. For example, direct light on a television could be a problem.
• Too much heat. Have a proper consultation beforehand to make sure the position of any skylight or roof window isn’t going to expose you to prolonged direct sunlight. This is especially important in the summer months.
• Breakage from falling objects. If there are trees surrounding your property, laminated glass could be a good option. In the even of a branch falling your roof or skylight won’t shatter.
• Leaks. Investing in poor quality equipment or having someone untrained do the installation can result in leaks. This'll either let water in or heat out.

What frame options are there?

Once you’ve opted for a skylight there are a number of different frame options available. A variety of manufacturers offer uPVC, wood and aluminium capped frames. And with a wide choice of colour and particular design elements it’s possible to find a skylight or roof window that fits perfectly with the aesthetic and practical demands of your room.

‘Think about your internal environment and what matches your décor,’ says David from Sterlingbuild. ‘If you have white uPVC windows then a white finish roof window will match perfectly. In addition, depending on the room the window is being fitted in different finishes suit different needs. A PVC or polyurethene window is designed for high moisture areas. This is perfect for a kitchen or bathroom.’

What’s the cost of adding a skylight?

There are many different factors which will contribute to the cost of installing a skylight  in your property. Firstly, there are inexpensive skylight and rooflight options available. Basic rooflight units can be found at DIY outlets for £100 to £150.

Going bespoke, naturally, is more expensive and depending on your particular needs and specification. In terms of price at least, the sky’s the limit. When it comes to cost, David from Sterlingbuild explains: ‘It entirely depends on what you’re looking for, the scale of the project and your budget. Before looking to purchase a roof window you need to decide the type of roof window required and where it will be fitted.'

Installation costs must also be factored in. Going cheap either in terms of the skylight unit itself or the installation could end up costing you dearly in the long term. You might regret going for a cheap option if you have to replace a leaky poor quality skylight or make repairs resulting from poor installation.

What size of skylight do I need?

It might seem like a no-brainer – the bigger the skylight, the more light you get flooding a room. But when choosing the size of your skylight and its positioning you should consider the particular practicalities of the room and how it’s used.

Consider the style of your property, both inside and out. A modern, contemporary interior may benefit from large, expansive areas of glass. But what works for the modern home might look a little out of place in more traditional homes and interiors.

Are there standard size skylights?

Rooflights can come in all shapes and sizes,’ says David Mayo from Sterlingbuild. ‘Some come as standard or you can get a bespoke, made-to-measure fit depending on what you’re after. One of the key considerations is the right balance and spread of light. So in many occasions two smaller windows allow for better light distribution than one large window.’

What about bespoke?

‘Our roof lanterns are made to measure’ says James Upton, Managing Director at Westbury windows and joinery. ‘They can choose square, rectangle or octagonal for the lantern shape. If a customer is looking for an oversized roof lantern, we would usually advise to go for two smaller ones. Or we would need to include tie bars to help support the weight of the lantern.’

Do skylights make the room hotter?

With greater levels of light in a room comes increased levels of heat from the sun’s rays. Planning and the positioning of your roof light is key. This ensures you don’t end up with a room that is either too bright or too warm to comfortably spend any time in.

‘There are a few things you can think about to mitigate solar gain in the hotter months,' says David of Sterlingbuild. ‘Internal and/or external blinds are the most pocket friendly option . You can choose roof windows that will open and close or have a ventilation flap. Or you can opt for a glazing that will reflect UV rays’.

Solar control glass is a special type of glazing that reflects the sun’s rays and limits the amount of heat skylights let into a room. As well as offering UV protection they can help reduce glare while maximising the amount of light.

Do I need planning permission for a skylight?

In most cases, the answer is no. David from Sterlingbuild explains: ‘Generally there isn't a need to apply for planning permission, as long as the following limits and conditions are met and it is not part of an extension project.

• Any windows installed must protrude no more than 150mm above the existing roof plane
• No alteration can be higher than the highest part of roof or stand out above the roof ridge
• Side-facing windows are to consist of obscure glazing for privacy purposes and should not be openable unless 1.7m above the floor

There can be exceptions for listed building or conservation areas. It's always best to check with your Local Planning Authority before starting any work.

Can I install a skylight in a conservation area?

Planning permission is always required if your building is listed,' says James from Westbury. ‘Additionally, if you live in a conservation area or a location of outstanding natural beauty, you are required to obtain planning permission if you wish to change the appearance of your home’.

‘It can be done,’explains David from Sterlingbuild, ‘but it’s imperative you check with your local planning authority before carrying out any work. Especially if you live in a listed building with an Article 4 direction.’

Can you install a skylight yourself?

Many skylight and roof window manufacturers offer installation as well as “supply only” service. That is, the skylight or window unit is delivered and you make the arrangements to have it fitted.
Unless you are a particularly skilled DIY-er installing a rooflight yourself is not recommended. On the surface, what might seem like a fairly straightforward procedure could end up costing you a lot of money.

‘You can install a skylight yourself,’ says David from Sterlingbuild. ‘But we really would strongly advise against, unless it’s your profession. The risks and financial cost of getting it wrong far outweigh the costs involved to get a very good builder to install one, so it’s best to play it safe and leave it in the hands of an expert.’