Multiwall polycarbonate sheets offer the insulation air space to reduce thermal energy transfer and create connective ribs between both sides for stranger structure and higher impact resistance. Therefore, multiwall polycarbonate is lighter weight than solid polycarbonate sheet, but same strength. Comparing with the plexiglass sheet, it is lighter weight, but stronger. The normal structures are twin-wall, triple-wall, four-wall, five-wall, seven-wall, sometimes, it offers the plugging structure and is used as roofing panels and facade system.