Practical advice for choosing a rooflight for your home
Updated: Jan 15
Rooflights, or skylights as they are often called, are an excellent way to illuminate your home as they let in light from the brightest part of the sky and are not generally affected by external obstructions, such as tress or other buildings.They provide an even distribution of light and can brighten the dark areas in a room that vertical windows could never reach.
Of course, in applications such as loft conversions they may be your only option to let in light. However, they are also a popular choice for other parts of the home where the ceiling has the potential to be opened up, and can make an excellent addition to kitchens, bedrooms, bathrooms and living spaces.
When specifying rooflights there are other aspects to consider beyond its shape, size, and the materials that it is made from. However, with so many options available, choosing the most suitable rooflight for your home can be anything but straightforward and there are a few key things to consider when deciding which product is best for you.
Choosing the right frame
The first thing to consider is the type of materials that are available for the rooflight frame. There are many different types of rooflight on the market catering for the modern contemporary style through to a more traditional look and feel.
Steel is the obvious choice for period properties and barn conversions, but they are now also being more frequently used in sleek new contemporary houses. Timber is a long-time favourite on homes of any style, but getting onto the roof to maintain the timber can be an awkward task. PVCu is also an option and is often the cheapest, but it will not provide the slim frames that metal is capable of, nor the natural look of wood.
The important thing is to select a rooflight that matches the look and feel that you are trying to achieve with your home, as it should blend in with your roof and the materials used throughout the rest of the house.
Once you have chosen the most appropriate material for your rooflight, you then need to consider the glazing options. Glazing can also be a tricky subject when specifying a rooflight, not least because there are so many different types of glass and glazing system available.
Aside from thermal performance you need to decide if you need toughened glass, for additional safety and protection against falling objects. Toughened glass does not mean that it is suitable to walk on, so if you need to stand on a rooflight it will require specialist glazing.
Self cleaning glass is another option. This technological breakthrough was introduced to the UK in 2002 by Pilkington, and is effectively the same as conventional glass, but with a specially developed coating on the outside, that once exposed to daylight, reacts in two ways. Firstly, it breaks down any organic dirt deposits through a photocatalytic process, and secondly, when it rains, instead of forming droplets, the water spreads evenly over the surface and takes the dirt off with it. It is kinder to the environment than ordinary glass and it is the ideal choice for situations where cleaning will be costly or difficult.
You also have the option for double or triple glazing. This is probably fairly obvious, but you should always opt for triple glazing if budget allows as this will have a significant impact on the thermal performance of the rooflight. Few rooflight companies will offer triple glazing as standard, so be aware of this when you are gathering and comparing quotes.
It is also possible to have solar control glazing, which incorporates invisible layers of special materials on the glass that has the dual effect of allowing sunlight in, while repelling solar heat. Allowing sunlight to pass through your rooflight while radiating and reflecting away a large degree of the sun’s heat means that your indoor space stays bright and much cooler than would be the case if normal glass were used. Solar control glass is not necessarily coloured or mirrored glass, although such finishes can be applied for aesthetic purposes if desired.
Conservation style rooflights
If you have a Listed property or live within a Conservation Area, you may be restricted in the type of rooflight you are allowed to install and the chances are that you will need a traditional or conservation style rooflight that complies with strict building regulations.
The legislation around conservation rooflights state that new openings should generally be kept to a minimum and should be of a simple form that respects the building's character.
Dormer windows are not usually appropriate, so any new window openings in the roof will likely need to be rooflights, and in most instances metal conservation-style rooflights which sit flush with the line of the roof.
There are specialist rooflights that are manufactured for the heritage property market and conservation rooflights are easily recognised by their low profile which means they sit flush and remain unobtrusive to the building's original architecture. Another characteristic is their slender appearance as conservation requirements stipulate that a minimal amount of framework should be visible, particularly if rooflights are placed next to each other.
Another feature of a genuine conservation rooflight is the glazing mullion (glazing bar) which separates the glazing into sections. This follows the traditional conservation rooflight design and not only provides a more authentic look but offers increased strength for the opening section.
There are a number of manufacturers who claim to offer conservation roof windows but have opted to remove the traditional bar in favour of sticking something to the double glazed unit. Not only does this risk damaging self-clean glazing or worse, having it fall off after a few years, it also significantly detracts from the original conservation rooflight appearance.
If your property is Listed you will need to work closely with your local authority before making changes to the building fabric. An excellent resource to find out more on this topic is the Listed Property Owners Club, www.lpoc.co.uk.
Maintaining your rooflight
Maintenance of your rooflight is often something that manufacturers will be uncomfortable discussing with you, as they are all too aware of the difficulty in achieving this. However, the fact is that, like most any other part of your home, it will require a degree of care to maximise its lifespan.
Proper maintenance is particularly important if you are specifying a metal product; in which case it is highly recommended that you opt for a 316 stainless steel frame. Not only is this a significantly stronger material that can withstand greater stress and tolerance levels, but more importantly it is much less susceptible to rust.
It is widely accepted that mild/carbon steel will start to rust the moment that it comes into contact with the atmosphere. While steel rooflight manufacturers will protect steel with a paint application, the quality and level of maintenance provided by the homeowner will still determine the lifespan of the product. Now in the UK, where it rains (a lot!), a mild steel rooflight which is in direct contact with rainwater on a regular basis is eventually going to rust without regular maintenance. Furthermore, if you are fortunate enough to live within 5km of the coast, then the risk of the corrosion will be both fast and significant, due to the elevated salt content in the atmosphere.
It is advisable to check the manufacturer’s warranty when it comes to your responsibilities concerning maintenance, as you could be expected to clean and maintain your rooflight as often as 4 times a year in order to keep your guarantee valid! Which is obviously not ideal for anyone who has neither the ability nor inclination to climb up their roof every few months!
Rooflights and environmental performance
Consideration must be given to thermal performance and improving carbon and energy reduction in buildings. Part L of the building regulations is one of the tools used by the government to achieve these objectives. These regulations are subject to continual change and are set to change again in 2020, as the UK Government continues its drive towards greater thermal efficiency in house building.
Rooflights can have a major impact on the overall energy consumption of a building, cutting energy costs by reducing need for use of the electric lights. However, there are some products that perform well above the minimum recommended environmental standards that could bring about even greater benefits in terms of thermal performance. So deciding on the right materials, of which the choice is plentiful, will be key.
Whatever your choice of material it is important that you check the energy rating performance and U Values of the glazing. It is worth asking exactly how each product performed under test conditions as there are many variables within the test that will differentiate between an average performing rooflight and an excellent one.
Make sure you are comparing like-for-like
As with most things in life, you tend to get what you pay for, and this is particularly true when comparing the rooflight market. Prices often reflect the quality of manufacturing and materials used to produce roof windows. While prices may vary considerably, there is good reason for this and the difference in quality between the bottom and high end of th rooflight market can be night and day.
The rooflight may be one of the last things that you budget for, but it is also one of the most important finishing touches to your home. Opting for the cheapest product may come back to haunt you in the long run.