Rooflights

Good overhead day-lighting is vital.

Properly designed it will provide:

  • red A cost effective and efficient means of achieving the required ISBEM rating for the building

  • red A substantial improvement to productivity and occupancy morale

  • red An economic and proven means of smoke venting the premises in the event of fire.

 

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?

  • red 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.

  • red 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.

  • red 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.

  • red 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.

  • red 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,

  • red Quality manufacture, sensible detailing and skilled installation equals good low maintenance roofing.

  • red 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.

  • red 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!

Jim Patterson - Technical Manager.

 

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