April 2018

Rooflights
SHEDDING LIGHT ON ROOFLIGHTS
By Andy Veater, Field Services Engineer South at Kingspan Light + Air
There are lots of benefits to introducing more
natural light into buildings. From a practical
point of view, it reduces the need to switch
on lights during the day, saving energy and
helping to keep electricity bills down. There has
also been lots of research that has shown
exposure to daylight can have a positive effect on
people’s health, wellbeing and productivity in a
variety of settings; from schools and hospitals to
workplace environments. In light of this growing
demand, it is important for roofing contractors to
understand the different types of rooflights
available, how they are installed and what
advantages they can offer.
In-plane vs. out-of-plane
As more building owners recognise the benefits of
daylighting, it is not only new buildings which are
being designed with the introduction of skylights
in mind, but retrofit applications are becoming
increasingly popular too. As such, it is important
to consider how certain rooflight designs can be
integrated within existing roof systems.
There are two key types of roof profiles. ‘In-plane’
rooflights, such as the polycarbonate strips often
seen on the roofs of industrial units, sit
seamlessly within a roof system. They are often
preferred by designers, particularly on low or
visible roofs, as they maintain a smooth sightline.
However, unless they’re specifically
manufactured to integrate with the rest of the roof
system, these rooflights can be difficult to
properly seal and make weathertight, especially
in retrofit applications.
‘Out-of-plane’ rooflights, which sit above the
roofline, often offer a more robust solution. These
rooflights are typically mounted and fixed over a
prefabricated kerb. This kerb can be fitted into
openings cut in the existing roofing system, and
quickly and easily sealed with factory-fitted tape
and weather sweep flipper gaskets. This allows
for more of a margin of error when cutting and
means the rooflights can be installed
after the roof has already been
installed – perfect for retrofit
applications and speedy
delivery.
Daylighting design
As ‘out-of-plane’ rooflights don’t
have to match the profile of the roof,
more innovative designs can be used to get a
better overall performance of the rooflight. For
example, the Kingspan Day-Lite Kapture skylight
has a unique design using semi-spherical domes.
This unusual shape has been fine-tuned to
capture as much light as possible, even when the
sun is low in the sky in the early morning or late
evening.
The rooflight has another innovation: a layer of
glazing made up from microscopic prisms. These
so called ‘nanoprisms’ are really effective at
dispersing natural light. This not only prevents
uncomfortable glare or hot spots forming in the
room below, but it also enables daylighting to be
predictably modelled, like a light fitting, to
achieve the necessary daylight levels. As well as
making life easier for installers, precisely tailoring
the area of the roof dedicated to rooflights
(without losing out on that valuable daylight) can
also help to make the building more energy
efficient. Whilst rooflights typically have a worse
U-value than the area of roof around them,
increasing the amount of daylight that can enter
the building should mean lights can be kept off
for longer – cutting the electricity demand.
Getting the balance right makes all the
difference.
As a final benefit, the domed shape can also help
to transfer loads such as snow or leaves to the
side of the rooflight, preventing it from settling
and obscuring the natural light. Taking into
account the weather in the UK last month, this is
an important consideration!
Image: ‘Out-of-plane’ rooflights are typically
mounted and fixed over a prefabricated
kerb, offering a robust and weathertight
solution.
Safety measures
Whilst it is important to ensure
that any rooflight installed
meets the correct non-fragility
standards, an ‘out-of-plane’ rooflight
can also provide additional safety benefits.
Not least the fact that it is clearly visible, making
it unlikely for anyone to accidentally walk or trip
onto one.
A steel-welded security mesh that is fixed within
the dome of the rooflight is also recommended to
ensure it meets the highest safety standards
possible. Tested to the same non-fragility
standards as the rooflight, this mesh serves two
purposes: in the event of something, such as a
fallen tree in a storm, or someone dropping onto
and damaging the rooflight dome, or if it is
removed for maintenance, the mesh will prevent
anything from falling through it and causing
further damage or injury in the space underneath.
It also provides a visual deterrent for intruders
looking to gain access to the property via the roof.
Powder-coated white, the mesh does not affect
the light transmission.
Lighting the way
Rooflight designs are changing and improving all
the time. By taking advantage of the latest
developments – such as Kapture – installers can
make installations easier and safer whilst also
delivering a better end-result for customers. Win,
win for everyone!
Contact Kingspan Light + Air
01352 716100
www.kingspanlightandair.co.uk
@KingspanLandA
48 TC APRIL 2018