Tar and gravel roofing dates back to 4,000 B.C., when it ... especially if mold forms. What about solid drainage? Without it, ponding can result when water collects after heavy rains.

Watts ProLine RD1 PVC, ABS, or cast iron roof drain with aluminum alloy flashing clamp, and secured poly or cast iron dome. [See More] Drain Type: Roof Body Material: ABS (optional feature); Cast Iron ...