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. Materials Used for Flat Roof Installation 3. PVC (Polyvinyl Chloride): Offers excellent waterproofing https://flat-roof-installation-and-repair.trustedstandard.com