08/08/2026
🏠 Does the Slope of Your Exterior Window Sills Matter?
It may seem like a small detail, but exterior window sills play an important role in managing rainwater.
Sills should provide positive drainage away from the window opening. A flat sill—or one sloping toward the window—can allow water to collect at the opening and increase the potential for moisture intrusion.
Proper window installation relies on multiple components working together, including the sill, flashing, sealants, and weather-resistive barrier (WRB), to keep water out and direct incidental water back to the exterior.
At Jekel Inspections, we believe an inspection should be more than checking boxes. We strive to provide real value and practical insight while helping homebuyers better understand building science, construction quality, moisture management, and long-term home performance.