TL;DR
A rim joist is the framing member that runs perpendicular across the ends of the floor joists, capping the floor system around its perimeter and transferring wall loads down to the sill plate. In sheds and decks it doubles as the attachment plane for siding, trim, and ledger connections, and it stabilizes the joist ends against rotation.
What it means
A rim joist is the framing member that runs perpendicular across the ends of the floor joists, capping the floor system around its perimeter and transferring wall loads down to the sill plate. In sheds and decks it doubles as the attachment plane for siding, trim, and ledger connections, and it stabilizes the joist ends against rotation. Because it sits at the cold edge of the floor band, it is also one of a building's worst air-leakage and condensation zones.
Where it sits in the glossary
Rim joist 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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