What constitutes good design?
For years Architects, Surveyors and Roofing and Cladding
Contractors have routinely opted for the 10% rule originally
formulated to allow for pin-joint portal frame design. This "rule
of thumb" no longer applies. Consideration of the lighting level,
overall thermal efficiency, building use, methods of artificial
lighting and switching all need to be balanced at the design
stage.
It is a well documented fact that good direct and diffused
daylight enhances the human condition, it is also a fact that GRP
or polycarbonate roof-lights cannot provide good thermal
insulation, so can one be balanced by the other? Research by Brett
Martin and Filon has shown that the optimum level of roof-lighting,
for ISBEM purposes is between 12 and 15%, half as much again as
usually allowed!
Combined with energy saving lighting units automatically switched
by photo-electric cell roof-lighting dramatically reduces the
energy use and improves the efficiency of the building. This makes
it easier to achieve the ISBEM target, the running costs are
minimised, the work-force is happier and the building is vented in
the event of fire!
Having decided to incorporate roof-lighting how do we locate,
specify and detail them?
If the internal production or storage layout is known, or can be
forecast, locate lights over the work centres and aisles. Aim for
12 to 15% 0f the internal floor area.
Long narrow lights, up and down slope, are better than lights
across the slope,(providing more and better dispersed lighting) so
use as much slope length as practical. Avoid, where possible having
single span roof sheeting above or below the light - they are
liable to foot traffic damage. Do not forget that ridges can be
cranked sheets rather than flashings.
If using barrel vault type lights in standing seam systems try
taking the light over the ridge, avoiding expensive welded aprons
which are sure to be a maintenance problem in the future. Stop the
light short of the eaves to provide solid longitudinal access and
easier eaves or gutter detailing.
Composite panel roofs have to use so called factory sealed lights.
These are not sealed units on a par with double glazing! Composite
roofs are poor acoustically, more difficult than reputed to fit
properly and these roof-lights are expensive. Why settle for an
over priced second best? Use site assembled roofing and have good
thermal, acoustic and aesthetic performance at lower cost.
Euroclads' ELITE System roof-lights are the so called "man-safe"
variety although the weight is chosen for longevity rather than
safety. Such lights are but is fair wiser to treat all roof lights
as fragile, especially when visiting unfamiliar buildings since
except on very close inspection they all look alike. You should
allways treat Roof lights as hazards, highlight theie location on
the roof with poppy red capped fixings and consider providing
walkways or fall restreint to mark safe areas of traffic,
Quality manufacture, sensible detailing and skilled
installation equals good low maintenance roofing.
GRP and polycarbonate are thicker than steel or aluminium
sheeting, the corners are not as sharp, that accuracy of the
moulding may not match that of the roll-formed product so double up
on the side and end lap seals - in both liner and weather sheet,
use the best quality screws and sealing washers, fit closers all
round to retain the insulation and keep dust, insects and other
debris out.
Wipe down the liner and interlayer before fitting the top-sheet, a
little time and trouble during construction is easier, cheaper and
less hassle than return visits!
Euroclad are proud to partner Brett Martin within our "ELITE"
systems and all our Elite roofs have roof-light specifications and
details designed to provide the same life as the roof, 12 or 25
years. These can then be purchased as full kits as part of the
system from Euroclad so you can be sure of timely delivery, a full
compliment of components and the correct quality. They are also
designed to be simple to fit!
RSS feeds. View our latest news
stories. Subscribe to our RSS you can receive automatic
updates.