Road base calculator for North Dakota

For a 100-foot lane that is 10 feet wide and 6 inches deep after compaction, plan on about 31 tons of road base. Tonnage builds quickly on lanes, and free delivery is especially useful when 30 tons of hauling can normally rival the stone cost. Road base combines graded crushed stone with fines and weighs about 3,000 lb per cubic yard. It compacts into a firm layer for equipment yards, driveways, and roads. Where specifications permit, use the same calculation for recycled crushed concrete base.

Lane calculations

1. For a lane, measure its centerline length and calculate from the average width. For pads, multiply the length and width.
2. For light residential use, allow 4 inches compacted. Use 6 for daily vehicles and delivery trucks, or 8-12 on soft subgrade and under equipment.
3. For yards, divide cubic feet by 27; for tons, multiply by 1.5; leave +10% for compaction.

Lane coverage and tonnage

Build a lane for the next winter

• Remove organics before placing base. Topsoil beneath stone will pump mud through it, regardless of how deep the base is.
• Put woven geotextile over wet or soft subgrade before placing stone. It adds low-cost support beneath a lane.
• Place material in lifts no deeper than 4 inches, rolling each one before adding the next.
• Build in a 2-3% crown from the centerline to move rain toward the edges rather than into the base.
• For a cleaner, lower-dust driving surface, add #57 or driveway gravel on top.
• Handling 20-plus tons by hand can take a week. A box-blade tractor or skid steer can spread it in an afternoon, so include the machine in the budget.

Example: a 100-foot farm lane

For one hundred by ten feet at 6 inches, the calculation is 1,000 x 0.5 = 500 cubic feet = 18.5 cubic yards, about 28 tons, or 30-31 with the allowance. Plan on two tandem loads and arrange two drop points along the lane instead of one pile at the gate. Separate drops make spreading easier and reduce the need to move stone uphill.

Pads for RVs, containers, and equipment

Apply the lane calculation to pads, but select depth by axle load instead of the calendar. A 12 x 40 RV pad at 6 inches compacted takes about 12 tons. A 20 x 40 equipment yard at 8 inches takes 27. Because shipping containers bear down at four corners, use a full 8 inches plus fabric for container pads even on decent ground, or those corners can settle into the pad by spring.

Recycled concrete road base

Virgin road base and recycled concrete base compact and carry load in much the same way, while recycled material often costs less. Check county requirements first, since some specs call for virgin aggregate. For private pads and lanes, the calculation remains 1.5 tons per yard with the same lifts and crown.

Road base by ton or lane

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