What the base is and why it matters

The base is the compacted layer of crushed rock or decomposed granite that supports your turf, controls drainage, and locks in a smooth finish. Get it right and your lawn stays flat, fast draining, and low maintenance. Undershoot it and you fight sinking, ripples, and puddles.

Depth recommendations by project type

  • Residential lawns with stable soil: 3 inches compacted.
  • Pets or high foot traffic: 3 to 4 inches compacted for better stability and drainage.
  • Play areas and light sports: 4 to 6 inches compacted. Add a shock pad if fall safety ratings are needed.
  • Putting greens: 3 to 4 inches compacted base plus a 0.5 inch layer of fines for contouring.
  • Clay, expansive, or freeze-thaw regions: add 1 to 2 inches to the above depths.

Always compact in thin lifts and check that your finished grade sheds water away from structures.

Coverage quick reference by depth

Approximate square feet covered by 1 cubic yard at common depths:

  • 1 inch depth: about 324 sq ft
  • 2 inches depth: about 162 sq ft
  • 3 inches depth: about 108 sq ft
  • 4 inches depth: about 81 sq ft
  • 5 inches depth: about 65 sq ft
  • 6 inches depth: about 54 sq ft

These are estimates. Order extra for compaction, trimming, and grade corrections.

Examples: fast math you can trust

Example A: 400 sq ft lawn at 3 inches

  • Depth in feet: 3 inches = 0.25 ft
  • Volume in cubic feet: 400 × 0.25 = 100 cu ft
  • Cubic yards: 100 ÷ 27 = 3.70 yd³
  • Add 10 percent contingency: 3.70 × 1.10 ? 4.07 yd³
  • Order: 4.0 to 4.5 yd³ depending on site conditions

Example B: 25 ft × 20 ft area at 4 inches

  • Area: 500 sq ft
  • Depth in feet: 4 inches = 0.333 ft
  • Volume in cubic feet: 500 × 0.333 ? 166.5 cu ft
  • Cubic yards: 166.5 ÷ 27 ? 6.17 yd³
  • Add 10 percent: ? 6.8 yd³
  • Order: 7.0 yd³

Example C: Irregular shape

Break the space into rectangles or triangles, total the square footage, then compute volume using the chosen depth. Round up. It is cheaper than a re-delivery.

Choose the right base material

  • Crushed stone or Class II road base (3/4 inch minus): strong, compacts tight, drains well. Standard choice.
  • Decomposed granite (DG): clean finish and good compaction. Watch for fines in wet climates and ensure proper drainage.
  • Avoid round gravel or pea rock: it does not lock up under compaction.

Ask your supplier for a well graded aggregate that compacts to 95 percent modified Proctor or better.

Compaction and build sequence

  1. Excavate native soil to allow for your base depth plus turf thickness.
  2. Grade for 1 to 2 percent slope away from structures.
  3. Optional: install geotextile over subgrade for soil separation, especially on clay or silty soils.
  4. Place base in 2 inch lifts max. Lightly moisten and compact each lift with a plate compactor.
  5. Finish with a thin layer of fines (quarter inch minus) for a smooth, hard wearing surface.
  6. Install edging that can hold spikes or nails and contain the base.

Drainage and soil factors

  • Clay or poorly draining soil: use more open graded base under the top lift, or include a perforated drain tied to daylight.
  • Freeze-thaw zones: increase base depth and compaction to minimize movement.
  • Over hardpan: scarify or perforate the subgrade to reduce perched water.

Convert cubic yards to tons

Supplier pricing often uses tons. Multiply cubic yards by the material density.

  • Typical compacted densities: 1.3 to 1.7 tons per cubic yard depending on rock type and moisture.
  • Rule of thumb: yd³ × 1.5 = tons for many road base blends.

Example: 6.0 yd³ × 1.5 ? 9 tons. Confirm the exact density with your quarry or supplier.

Inch-to-foot depth shortcuts

  • 2 inches = 0.167 ft
  • 3 inches = 0.25 ft
  • 4 inches = 0.333 ft
  • 5 inches = 0.417 ft
  • 6 inches = 0.5 ft

Ordering tips from FusionTurf

  • Round up 5 to 10 percent for compaction, shaping, and waste.
  • Stage deliveries if access is tight or if rain is forecast.
  • Compact as you go. Do not place a thick lift and hope it locks up.
  • Confirm base depth matches your turf pile height to hit finished grade cleanly.

Want a zero guess estimate and a clean install plan? Connect with a FusionTurf pro at find.fusionturf.com. We will size your base, dial in drainage, and get you a quote that stands up in the field.