Roof Lantern Buying Guide

Roof lanterns are widely considered some of the most stunning roofing centrepieces available in today’s market and have long been admired for many years. Protruding from your roof like the great pyramids of Giza or light shining through to the room below from every angle are just some of the many reasons that make roof lanterns extremely desirable.

Whilst these engineering masterclasses are available for a relatively small outlay compared to times gone by, one thing that hasn’t got much easier is knowing which roof lantern is best for you and your home. This buying guide aims to help you understand our roof lanterns, how they can benefit you and most importantly and how to determine which one is for you.

The Bigger, The Better?

It is easy to throw everything you know about roof lanterns out the window and just go for the largest size possible for your home, but in many ways, this could be seen as counter intuitive. In our roof window buying guide, we mention that you can remedy too big or too small with artificial lighting or blinds as these are fixtures likely already in your home or could easily be implemented. With roof lanterns, this is very different.

Due to the sloping glass on all four sides of the roof lantern, it allows light to shine in at literally every angle and can not only be harder to remedy if you don’t get it right, but blinds for roof lanterns are a little more expensive than those available for roof windows.

One of the very first questions you need to ask and will know instantly is where the roof lantern is being installed and does it have a lot of natural daylight already. If you have large bi-folding doors and/or many vertical windows, then it may not be completely necessary to have an overwhelmingly large roof lantern in the first place.

Secondly, you need to ask yourself what its purpose is going to be. Most people select roof lanterns due to the unmatched natural daylight on offer, but some may want to highlight a specific section of a room. Maybe a sitting area so you can enjoy the daylight or a kitchen area for when you are cooking up a treat.

You will also need to know the size of your flat roof, in which the roof lantern will be installed into. It is uncommon to find roof lanterns spanning across the entirety of a roof and often, you don’t need to either. Despite it seeming small, a 1000 x 1000 mm roof lantern lets in 3 times as much light as a vertical window of the same size, due to its sloping structure.

A good ballpark figure is that the overall glazing area should cover at least 15-20% of the floor space in the room below overall. This ensures that you benefit from a natural flow of daylight of a significant amount, but not to the point that it is overwhelming nor insignificant.

Measuring Up

Now that you have an idea of the size you require, you now need to put plans into place for the installation and the first part of that is measuring up. As listed on our Korniche roof lanterns, all sizes are the external kerb dimensions. From this you can calculate how large your opening needs to be, and we will list an example here.

If you purchase a 1000 x 1000 mm Korniche roof lantern, your external upstand size, including membrane, needs to be 988 x 988 mm. This is to account for a 6 mm overhang all around the roof lantern. From there, your opening is solely dependent on the thickness of your upstand. It is worth noting that your upstand needs to be at least 69 mm thick as this is the thickness of your ringbeam.

If you opt for an upstand of 69 mm thick, multiply that number by 2, giving you 138 mm. You then deduct the 138 mm from the 988 x 988 mm external dimension, to give you a structural opening of 850 x 850 mm. To display another example, if you opted for a 75 mm thick upstand, multiply that number by 2 to get 150 mm. Take that away from the 988 x 988 mm external dimension and your opening would be 838 x 838 mm. You also need to ensure that your upstand is at least 150 mm high.

A Colour For Everyone

The Korniche roof lanterns are available in a wide variety of special colours, providing you know the RAL number of the colour you would like, but there are a small range of popular yet standard colour configurations to suit most people’s tastes.

The great thing about these standard colour configurations for the Korniche roof lantern is that there is no difference in cost, based on the option you go for. You have the choice of the following:

• White on White
• Black on White
• Grey on White
• Black on Black
• Grey on Grey

Ultimately, these come down to personal preferences and the overall style you would like to achieve inside and outside your home. Maybe you have grey vertical windows on the rest of your home but a sleek and contemporary style in the room below the roof lantern, meaning a grey on white configuration might do the trick. You may have grey bi-folding doors as well and would like a grey-on-grey configuration to compliment them both internally and externally.

Tint Anyone?

One of the last stages of determining the roof lantern for you is choosing the right glazing option. There are a variety of standard glazing options available that offer fantastic benefits regardless of what you are looking to achieve with your roof lantern. A graphic below will show the options, the kind of tints you can expect and how they can benefit you:

Like with the colour configurations, this is largely down to personal preference as it will have an effect on your overall aesthetics. However, should you require a roof lantern with a u-value of at least 1.1 for example, then the Ambi Aqua or Sunshade Blue will be the better options for you.

A common pattern that you may notice is that the larger the solar heat reflection is, the smaller the light transmission becomes, so if you want to find a nice middle ground between them all, then the Ambi Neutral or Ambi Blue may be the better option. Of course, you can always opt for clear glass if specifications such as solar heat reflection isn’t important to you, but light transmission is.

And Breathe..

Not quite finished yet. The final question is would you like some ventilation? As a bespoke specification, we can add opening vents into the roof lantern, should you like to allow fresh air into your home. Available with a manual screwjack option or electric motor operation, the vents are only suitable for rectangular roof lanterns with sizes from 1600 x 2350 mm or square roof lanterns in the size of 2150 x 2150 mm. Both width and length will need to be the same or larger than these dimensions to allow for a roof vent. For example, roof vents would not be possible in a 1500 x 2500 mm roof lantern.

Of course, some roof lantern enquiries have detailed and more advanced questions in play and may require further advice beyond our extensive buying guide. If you would like to discuss your enquiry in further detail or would like to know more about bespoke specifications such as colours, sizes and even glazing options, please contact our helpful sales team via telephone, e-mail or live chat, who will be more than happy to discuss this with you further.