What base course means
The base course is the layer of compacted gravel or crushed stone under a slab, patio or pavers that spreads loads and drains water.
Also called gravel base, compacted base.
Where it matters on a concrete job
Most settling and heaving traces to a thin or poorly compacted base. Price base depth and compaction honestly; it is the part the customer never sees and the part that decides how long the job lasts.
What the model code says
- Where a slab is below grade, a 4-inch-thick base course of clean graded sand, gravel or crushed stone goes on the prepared subgrade. (IRC 2021, Chapter 5)
Check which code edition your building department enforces for base course before you quote.
What it costs
The paver patio cost guide has the typical job at $4,900 and the usual range at $2,700 to $7,500. The guide shows its sources and what moves the price. The paver patio cost calculator prices a job line by line.
Work it out
- Free calculator: Paver patio cost calculator
- Cost guide: Paver patio cost
- Tools, templates and guides: Free concrete resources
Sources: 2021 International Residential Code, Chapter 5, Floors (ICC). Checked October 9, 2026.