TL;DR
An expansion joint is a full-depth separation built into concrete or masonry that lets adjacent sections move independently as temperature and moisture swell and shrink them, with a compressible filler keeping the gap open. It differs from a control joint, which is a shallow groove that merely steers cracking; an expansion joint isolates a slab from a foundation, stoop, or pool deck entirely.
What it means
An expansion joint is a full-depth separation built into concrete or masonry that lets adjacent sections move independently as temperature and moisture swell and shrink them, with a compressible filler keeping the gap open. It differs from a control joint, which is a shallow groove that merely steers cracking; an expansion joint isolates a slab from a foundation, stoop, or pool deck entirely. Failed, debris-packed joints transfer load between slabs and crack corners, which is why joint cleaning and re-caulking is routine concrete maintenance.
Where it sits in the glossary
Expansion joint is part of the Certifications 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
License: CC-BY-4.0 — quote freely with attribution to ProFix Editorial Team / ProFix Directory.