Clerestory Window System For Commercial Applications – Most often builders, using relatively short sheets of polycarbonate, can simply attach to horizontal girts at top and bottom of the sheet. The Base and Cap is used where the sheet joins and acts as a stiffener, eliminating bowing of the sheet. U-Profile Install Tips
Screws with Base & Cap Screw counting screws used in body of sheet and perimeter.
See 8 – 25mm Polycarb some are 20 Year – Lexan Thermoclear is clearly the industry leader