We have a flat roof with parapet wall (yes, I know).   A couple of issues have arisen that I'd like to address before they get any worse. The problems are a combination of crappy installation detail and crappy actual installation. The first is the junction between the outer edge of the parapet wall and the EPDM-based membrane that covers the roof. The current detail is pretty poor. The parapet wall slopes inwards slightly. There's an aluminium drip trim that hangs over the oute