October 30, 2025

On firm subgrade, plan 4–6 in (100–150 mm) of compacted aggregate above the geogrid for cars. On medium/soft soils, use 6–12 in (150–300 mm). Keep minimum 4 in cover over the grid, build in 6–8 in lifts, and add 2–4 in in freeze–thaw zones. Always adjust for load, soil, and drainage. Why Base Depth Matters？ […]