TL;DR
Compacted subgrade is the native soil beneath a slab, driveway, or pavement that has been mechanically densified, typically to 95 percent of its Proctor maximum density, before any gravel base goes down. It is the true foundation of the work above: soft or disturbed spots left under a patio telegraph upward later as cracks and settlement that no concrete thickness can outmuscle.
What it means
Compacted subgrade is the native soil beneath a slab, driveway, or pavement that has been mechanically densified, typically to 95 percent of its Proctor maximum density, before any gravel base goes down. It is the true foundation of the work above: soft or disturbed spots left under a patio telegraph upward later as cracks and settlement that no concrete thickness can outmuscle. Specs may require a proof-roll or density test, and the line item is worth seeing in any flatwork bid that involves fill or recently excavated ground.
Where it sits in the glossary
Compacted subgrade 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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