What is Sill Pan Flashing?

Sill pan flashing is the last line of defense against water that leaks into walls while building a home. The pan flashing is used to collect and direct—collect bulk water and direct it outside and away from the door or window frame. It is installed below windows and doors, and is designed to protect from water leaking through to wood which can cause significant structural damage and expensive repairs in the future.

There are four essential characteristics of a code compliant pan flashing system:

1. It has an outward slope of at least 6%

2. It is in a continuous piece

3. It extends at least 6 mm beyond the underlying covering

4. It prevents water from entering the walls to the lower corners of windows and doors


These four requirements suggest that simple membrane flashing systems simply aren’t enough because they are not sloped and do not whisk water away from the window sill or door frame. HomeFlash meets or exceeds all of these requirements and is easy to install. If you’re a homebuyer, builder or architect: