1. Install trusses and purlins with good quality materials. It can be high quality wooden, metal or stainless steel. The distance of trusses and purlins should be conformed to standard of supplier’s instruction. (The maximum purlin span for roof sheet is 850mm).
2. Install the roof sheets. Place them directly onto purlins that are attached to the roof trusses, beginning on the outside edge. The recommended length overlap is 200mm - 400mm. Close or seal off the ends with a wood or plastic strip under the roof sheet at each end. These will stop the entry of rain, wind and pests.
3. Pre-drill holes on the crest of roof sheet. Use a proper drill bit. Diameter of pre-drill holes must be 1-2mm more than the diameter of screw. Pre-drill holes on the end and side crest of the roof sheet, spacing the holes according to the wave.
4. Screw down the roof sheets through the pre-drill holes onto purlins with minimum 5 sets of screws in every square meter (m²). Continue across the roof until it is completely covered, lapping over the previous panel by one wave. Lapping over 2 wave in the heavy wind area. Adjust the lap so that the last panel completes thcoverage without making a cut lengthwise.
5. Complete the opposite side. If your roof is two-sided (and not just a single slope), repeat the installation on the other side of the roof, and install a corrugated ridge cap as you proceed across with the panels.
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