Why EPS Window Sills Fail in Rain—The Slope Mistake 85% of Installers Make
Most EPS window sill failures aren’t material defects—they’re installation errors that trap water and cause degradation within 18–24 months. The culprit: installers set sills level or with insufficient slope, allowing rainwater to pool instead of drain. A 2–4° slope outward cuts failure risk by 90%.