TL;DR
Sill pan flashing is the waterproofing layer built at the bottom of a window or door opening, lapped and sealed so any intruding water sheds outward onto the drainage plane. It can be a site-formed system of self-adhered membrane with a back dam, or a rigid prefabricated pan, and the IRC requires openings to be flashed per the manufacturer's or a registered design.
What it means
Sill pan flashing is the waterproofing layer built at the bottom of a window or door opening, lapped and sealed so any intruding water sheds outward onto the drainage plane. It can be a site-formed system of self-adhered membrane with a back dam, or a rigid prefabricated pan, and the IRC requires openings to be flashed per the manufacturer's or a registered design. Done correctly it makes the inevitable small leaks harmless; done wrong it funnels them straight into the subfloor.
Where it sits in the glossary
Sill pan flashing is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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