Rio Stone field guide
Base depth and site-preparation questions
Separate subgrade, excavation, drainage, base, bedding, surface, compaction, and finished elevation before estimating material layers.
A useful material request starts with a clear measurement, a defined use, and honest expectations about what still needs confirmation.
Read the ground before choosing a section
Identify native or fill soil, soft spots, organics, moisture, pumping, expansive behavior, previous trenches, roots, utilities, drainage paths, and existing settlement. Record pedestrian, vehicle, equipment, wall, or point loads and the required finished surface. A base thickness copied from another job can fail when subgrade, climate, drainage, or loading differs.
Draw the layer stack
Show existing grade, excavation, prepared subgrade, separator or reinforcement when designed, drainage, aggregate base, bedding or leveling course, surface material, edge restraint, joints, and finished elevation. Label loose placement and compacted thickness distinctly. Transitions at doors, curbs, drains, paving, soil, and accessible routes often control the available depth and should be solved before ordering.
Calculate each layer independently
For a uniform rectangular layer, cubic yards equal square feet × compacted depth in inches ÷ 324. Use separate lines for areas or depths that differ. The amount delivered loose may exceed compacted geometry, but the applicable conversion depends on material gradation, moisture, equipment, lift thickness, and target density. Obtain a verified factor rather than inventing one.
Prepare and verify in stages
Protect benchmarks and utilities, remove unsuitable material as directed, proof or inspect subgrade when required, place material in approved lifts, control moisture, compact with appropriate equipment, and test where specified. Check elevations and drainage before covering each layer. Stop if pumping soil, unexpected fill, standing water, buried work, or inaccessible compaction changes the assumptions.
Before requesting pricing
- Document intended use, loads, soil condition, drainage, utilities, roots, slopes, frost or expansion concerns, and finished grade.
- Measure every layer at its compacted design depth and keep excavation volume separate from imported material.
- Use project or manufacturer details for section thickness; no universal base depth fits every site or surface.
Frequently asked questions
What is the standard base depth?
There is no universal depth. Surface system, load, subgrade, drainage, climate, accessibility, manufacturer requirements, and design determine it.
Is loose depth equal to compacted depth?
No. The relationship varies by product, moisture, lift, equipment, and target density. Keep both values labeled and use verified guidance.
Can fabric fix weak subgrade?
Not by itself. Separation or reinforcement must be selected and detailed for the actual soil, loads, drainage, aggregate, and installation.