How Much Road Base for a 18x36 Parking Pad?
How much road base for a 18x36 parking pad is a quick volume problem. 648 square feet at 4 inches comes to 8.00 cubic yards. Road base usually weighs about 1.4 to 1.65 compacted tons per cubic yard, so plan on roughly 12.0 tons.
Volume and tonnage calculator →The math for a 18x36 parking pad
- Area: 18 × 36 = 648 sq ft.
- Depth in feet: 4 ÷ 12 = 0.333 ft.
- Cubic feet: 648 × 0.333 = 216.0 cu ft.
- Cubic yards: ÷ 27 = 8.00 yd³.
- Tons: × 1.5 = 12.0 tons.
The volume and tonnage calculator does this for any size.
Road base needed by depth
| Depth | Cubic yards | Tons (approx.) | Tons +10% |
|---|---|---|---|
| 4 in | 8.00 | 12.0 | 13.2 |
| 6 in | 12.00 | 18.0 | 19.8 |
| 8 in | 16.00 | 24.0 | 26.4 |
About road base
Road base is meant to be compacted at close to the right moisture. Dry base rock does not lock up well; a light spray of water before rolling helps. 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. For parked vehicles, the depths in the table above are a reasonable starting range.
Ordering tips
- Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
- Delivery size. 13.2 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.
Where road base fits
Good uses:
- 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 8x16 area at 2 inches takes about 1.2 tons.
- Weight used here: about 1.5 tons per cubic yard.
Common estimating mistakes
- Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
- Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
Questions people ask
How many tons of road base for a 18x36 parking pad?
About 12.0 tons at 4 inches deep, or 13.2 tons with 10 percent extra.
How many cubic yards is a 18x36 parking pad at 4 inches?
About 8.00 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 18x36?
648 square feet.
Related guides
- Crushed Stone vs Gravel: Differences and Best Uses
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Many Tons of Gravel in a Dump Truck? Loads and Coverage
- How Much Does a Ton of Gravel Cover? Depth Chart
- How Much Road Base for a 18x24 Parking Pad?
- How Much Road Base for a 18x30 Parking Pad?
As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.