The Basics of Flat Roofs A flat roof is a roofing system that’s nearly level, with a slight pitch to allow water drainage. They provide additional usable space, such as rooftop gardens or HVAC system placement. 1. EPDM (Ethylene Propylene Diene Monomer): A durable and flexible rubber membrane. Flat https://flat-roof-installation-and-repair.trustedstandard.com