This project addressed a high-risk roof-to-wall transition where a valley was directing heavy water flow into a low-slope section with no proper drainage. Over time, debris buildup and winter conditions led to water backup and active leaking. Instead of performing a temporary repair, we redesigned the system. The affected shingle area was removed, and the section was converted into a fully sealed EPDM rubber roofing system. We extended the membrane up the wall transition and created positive pitch to direct water away from the structure. This solution eliminates water pooling, prevents ice dam formation, and provides long-term waterproof protection in an area where shingles alone would continue to fail.