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How Much Road Base for a 12x30 Parking Pad?

A 12 by 30 foot parking pad is 360 square feet. How much road base for a 12x30 parking pad depends on depth: at 4 inches it is about 4.44 cubic yards or 6.7 tons. Suppliers usually sell by the ton, so the tonnage is the number to give them.

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The math for a 12x30 parking pad

  1. Area: 12 × 30 = 360 sq ft.
  2. Depth in feet: 4 ÷ 12 = 0.333 ft.
  3. Cubic feet: 360 × 0.333 = 120.0 cu ft.
  4. Cubic yards: ÷ 27 = 4.44 yd³.
  5. Tons: × 1.5 = 6.7 tons.

The volume and tonnage calculator does this for any size.

Road base needed by depth

DepthCubic yardsTons (approx.)Tons +10%
4 in4.446.77.3
6 in6.6710.011.0
8 in8.8913.314.7

About road base

Road base (also called base rock, ABC, or Class 2 base in different states) is a graded mix of stone and fines made to compact into a load-bearing layer. If the yard sells by the cubic yard instead of the ton, use the cubic-yard column directly.

Preparing the parking pad

Dig out organic soil, compact the subgrade and set an edge so the stone does not migrate onto the lawn. A pad that holds parked weight for long periods benefits from a dense base under the surface stone. This parking pad sees parked vehicles, so match the depth to that load rather than to the minimum.

Ordering tips

  • Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
  • Delivery size. 7.3 tons fits in a single typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
  • Bulk vs bags. At this size bulk delivery is usually the practical choice.
  • Where it drops. Have the truck dump as close to the parking pad as firm ground allows.

Good and poor uses for road base

Works well for:

  • Base under asphalt and concrete
  • Gravel roads and drives
  • Equipment and shed pads

Think twice for:

  • Drainage layers
  • Decorative surfaces
  • Surfaces that will stay uncompacted

Quick reference numbers

  • Per inch over 100 sq ft: about 0.46 tons of road base (0.31 cubic yards).
  • Per inch over 1,000 sq ft: about 4.6 tons.
  • Another size for comparison: a 14x28 area at 3 inches takes about 5.4 tons.
  • Weight used here: about 1.5 tons per cubic yard.

Where estimates go wrong

  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
  • Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
  • Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
  • Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.

Questions people ask

How many tons of road base for a 12x30 parking pad?

About 6.7 tons at 4 inches deep, or 7.3 tons with 10 percent extra.

How many cubic yards is a 12x30 parking pad at 4 inches?

About 4.44 cubic yards.

How much does a cubic yard of road base weigh?

Usually around 1.4 to 1.65 compacted tons, depending on stone size, fines and moisture.

How deep should road base be for a parking pad?

The table above shows 4 to 8 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 12x30?

360 square feet.

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