Is a Sill Pan Necessary

Most residential builders understand that window rough openings need sill pan flashing — either a site-built sill pan made with peel-and-stick tape, or a commercial sill pan made from metal or plastic. … Not only that: sill pan flashing under exterior doors is code-required.

What is the purpose of a door sill pan?

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.

Can you use flashing tape instead of sill pan?

Using flashing tape. Manufacturers make ready-made sill pans with proper slope and drainage that cost around $30. But often, builders don’t think about the sill pan until they’re installing the door. So rather than hold up construction, they’ll often simply fashion a sill pan out of flexible flashing tape.