For Heat Protection: Use Multiwall Polycarbonate. The hollow chambers provide better thermal insulation, keeping the area underneath cooler than solid sheets. For Aesthetics: Use Solid/Compact Clear Sheets. They look exactly like glass but are 250 times stronger. They are perfect for modern sit-outs. For Durability: Ensure the sheets are UV-coated. Chennai’s intense sun can turn cheap polycarbonate yellow and brittle within 2-3 years if they lack proper UV protection.