In this Roofing Road Trip, Heidi J. Ellsworth meets with Stephen Patterson, RRC, PE and Dr. Madan Mehta, PE, PHD about the unprecedented change in roof drainage design. A new publication on Roof Drainage – Second Edition, this book was funded by the CI-IIBEC Foundation. They will share how in this second edition; they are responding to an unprecedented change in roof drainage design from what has been used for more than a half century. Until recently, the plumbing codes assumed that the flow through a roof drain is the same as the flow through a vertical leader of the same diameter. Several investigations and roof-collapse forensics have shown that our assumption has been incorrect. Don’t miss this extremely important discussion.