Adjust Base Depth for Slopes and Soil Conditions
At 1:51 in
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What happens here
Clarify the rule for base depth depending on the terrain. On a flat, level surface, dig 1 foot below grade, providing 6 inches for rock and 6 inches for the base block. This ensures one full course of block is buried. On a slope, 1 foot is not enough. The number of buried courses depends on the steepness of the slope. For example, a 3:1 slope requires a minimum of two buried courses, leading to an 18-inch subgrade cut (6 inches rock + 12 inches block). A steeper 2:1 slope may require three or four buried courses for added stability. Always err on the side of caution with steeper slopes and increase buried courses.
Goal: Determine the appropriate base depth based on terrain and soil stability.
Tools and materials
- Tape Measure — Measuring depth of subgrade cut
- Geogrid — Reinforcing the base in soft or questionable soil conditions