TL;DR
A control joint is a deliberate groove tooled into fresh concrete or saw-cut within hours of finishing, creating a weakened plane so inevitable shrinkage cracks form neatly along the line instead of wandering across the slab. Effective depth is one quarter of the slab thickness, an inch deep in a four-inch slab, and timing matters: cut too late and the slab has already cracked where it pleased.
What it means
A control joint is a deliberate groove tooled into fresh concrete or saw-cut within hours of finishing, creating a weakened plane so inevitable shrinkage cracks form neatly along the line instead of wandering across the slab. Effective depth is one quarter of the slab thickness, an inch deep in a four-inch slab, and timing matters: cut too late and the slab has already cracked where it pleased. They are concrete's version of perforation lines, managing cracking rather than pretending to prevent it.
Where it sits in the glossary
Control 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
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