This is a Mukilteo Commercial Flat Roof where we installed a new mechanically attached 60 mil IB Roof System after removing the old hot tar roofing assembly. Because the parapet walls were concrete "tilt-ups," we used IB Roof System's special CB-10 concrete fasteners and wrapped all walls with PVC to ensure a watertight roof system. This is especially important because cutting counter flashing in on concrete walls can be extremely problematic. Moreover, the terminate and caulk method most contractors use will fail and result in leaks.