Eternit FarmTec Polycarbonate Rooflights

Polycarbonate rooflights
Eternit supplies agricultural grade polycarbonate rooflights, suitable for use with the FarmTec fibre cement sheets. These are classified non-fragile class C but should be always treated as fragile.
Description FarmTec UV resistant polycarbonate sheet
Thickness Approx. 1.3mm
Weight 1.88 kg/m²
Fragility rating Class C
Fire rating Class 1Y (BS 476 part 7)
Colour Clear
Light transmission 88%
U-value 5.68 W/m²K
Storage Rooflights should be stored on a flat, horizontal and dry surface. Stack height should not exceed 1m. It is recommended that sheets are stored indoors where possible. If sheets are being stored outdoors, they must be covered with an opaque cover, tightly secured, to protect from wind, rain and sun.
Transport and handling Rooflights should be transported horizontally on flat, sturdy pallets, equal to or longer than the longest sheet. Short sheets should be stacked on top of the longer ones. All panels should be secured and properly fastened to the pallet during transportation. Rooflights must be handled with care all times as it is a glazing material. NEVER walk on the rooflights if access to the roof is required, use walking boards placed across at least three purlins to spread the load. Sheets must be lifted cleanly off the stack. Sheets in excess of 3m long should be carried by more than one person.
Cutting When cutting the sheets, you must support the sheet to avoid stress and vibration. The blade should only protrude through the sheet by about 10 mm. If the blade is too far through the sheet, the blade ‘chips’ at the sheet producing a bad cut.
Cutting multiple sheets can be achieved but extra care must be taken. Polycarbonate sheets can be cut with a variety of tools:
• Fine tooth hand saw: hold the saw at a shallow angle and cut with slow steady strokes.
• Jig saw fitted with a metal cutting blade
• Band saw fitted with a high-speed metal cutting blade
• Circular saw fitted with a diamond grit blade.
• Angle grinder with thin metal slitting disc.
The basic blade characteristics which we have used for multiple sheets is:
Circumference speed = 2400 m/min Tooth spacing = 10 mm approx. Diameter = 250 mm approx. Clearance angle = 20-30° Rake angle =15°
Drilling Polycarbonate sheets can be drilled by hand or power drills. If using a power drill, set to a slow speed. Support the sheet underneath the hole position to avoid vibration. When drilling holes always allow for thermal movement. Support the rooflight directly under the drill.
Fixing instructions
The use of translucent sheets at the edge of the roof surface must be avoided. The combination of translucent sheets under fibre cement accessories is not recommended.
Filler blocks Polycarbonate sheets must be supported at each purlin position, using profile filler blocks or the FarmTec Fibre Cement sheet.
Sealant Polycarbonate sheets must be sealed using a 10mm diameter butyl strip sealant. Place a row of sealing strip either side of the purlin centre line, separated by about 10mm at the end laps and top of the polycarbonate sheets (so the fixing is in between the 2 strips of butyl). Side laps are single sealed, with the butyl strip positioned outside the line of side lap laplox fixings. (Ensure that butyl strip being used is compatible with polycarbonate.)
Mitring The polycarbonate sheets do not require mitres, and the corresponding corner of the FarmTec sheet should also be unmitred. Since the build-up of compound layers at end lap situations does not occur.
Fixing positions Polycarbonate rooflights should be fixed through every corrugation at the end lap and intermediate purlin using the same fasteners for the FarmTec sheets, apart from the side lap corrugations. Polycarbonate roofllights should be pre-drilled with an 11mm hole at all purlin fixing positions. (This is for polycarbonate sheets only and not the fibre cement sheets).
In addition, self-sealing fasteners with a synthetic rubber shank (laplox) or seam bolts and washers with a wide bearing, should be used at 300-400mm centres for side stitching to the adjacent sheet the hole should be pre-drilled to suit the selected side stitch fixing chosen. It is advisable to use weatherproof caps, and washers where possible, that are a distinctly different colour to the fixings for the rest of the roof. The rooflight fixings act as a warning that this location is always fragile and should be avoided.
Conventionally, poppy red caps are used for rooflights.
Panel orientation Ensure that the clearly marked UV protected surface of the polycarbonate rooflight is to the outside. Polycarbonate rooflights must always be installed with the corrugation running vertically, or up- slope.

Please note, the image representing each colour is for reference only. The product is represented by the first image.