See what can happen to multiwall polycarbonate on less than 5% (1/12) pitch
– Condensation will not effectively drain out of the sheet.
– Leaks at lower edge much more likely.
– Capillary action will suck water up the channels.
– Mold & mildew will gather, turn black and never go away.
Worst case photo, heavy pollen, virtually no slope, never washed.
Polycarbonate Greenhouse and Sunroom Building Supplies