TL;DR
The subgrade is the native or engineered soil surface, graded and compacted, on which a pavement structure or slab system is built; everything above it, including subbase and concrete, depends on its stability. Crews proof-roll it with a loaded truck to find soft spots, which get excavated and replaced or stabilized before any stone goes down.
What it means
The subgrade is the native or engineered soil surface, graded and compacted, on which a pavement structure or slab system is built; everything above it, including subbase and concrete, depends on its stability. Crews proof-roll it with a loaded truck to find soft spots, which get excavated and replaced or stabilized before any stone goes down. Expansive clays and organic soils are the problem subgrades, and on bad ones engineers specify moisture conditioning, geotextile, or thicker sections.
Where it sits in the glossary
Subgrade 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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