Adequate lap up the side wall, a firm connection, and a careful top flashing are important.
This EPDM roof turns about 10 inches up the wall (8 inches is BOWA's normal requirement), and a termination bar holds it firmly in place. Sealant at the top edge prevents water from leaking behind it. Finally, the weather-resistive barrier (WRB) on the wall is pulled out in front of the roofing material.
A tall stainless steel Z-flashing connects a PVC roof to the stucco to be installed later. This maintains clearance and allows the roof to be reworked later.