This is a project located in Redmond, WA where we installed a 60 mil PVC membrane by IB Roof Systems along with a flat roof tapered system. When we first responded, we found that the PVC roof system then in place was not installed correctly. Specifically, it was attached with hammer tacker staples, had no vapor barrier or slip sheet underneath and was not terminated properly at roof edges. The old roof system was 8 years old with leaks developing within the first 2 years. Frustrated with the previous contractors workmanship (or rather, lack of), the owners looked to an IB certified contractor. Don't trust your flat or low slope roofing needs to the average roofer. Call a flat roof specialist, Call an IB Contractor. Call PRP. 206.919.3538