TL;DR
Rail infill spacing is the clear distance between the balusters, cables, or panels that fill a guardrail, governed by the IRC rule that no opening may pass a 4-inch sphere. The limit exists to keep a small child's head and body from slipping through, and inspectors physically test it with a gauge ball.
What it means
Rail infill spacing is the clear distance between the balusters, cables, or panels that fill a guardrail, governed by the IRC rule that no opening may pass a 4-inch sphere. The limit exists to keep a small child's head and body from slipping through, and inspectors physically test it with a gauge ball. Cable systems deserve special care because cables deflect—tension and intermediate posts must keep the gap under the limit when pushed, not just at rest.
Where it sits in the glossary
Rail infill spacing 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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