Understanding Flat Roofs A flat roof is a roofing system that’s nearly level, with a slight pitch to allow water drainage. Why Opt for Flat Roofs? They provide additional usable space, such as rooftop gardens or HVAC system placement. Materials Used for Flat Roof Installation 3. PVC (Polyvinyl Chloride): https://flat-roof-installation-and-repair.trustedstandard.com