Number 1 Stone: Size, Weight, and When to Use It
Number 1 stone is one of the largest standard crushed stone sizes, with most pieces falling roughly between 1 1/2 and 3 1/2 inches. Like other single-size clean stones, it has very few fines, so it drains freely and does not pack into a smooth surface. It is used where size and stability matter more than a finished surface: construction entrances, stabilizing soft or muddy ground, the bottom layer of a driveway on poor soil, and some drainage work. It weighs about 1.3 to 1.5 tons per cubic yard and is almost always covered with smaller stone before anyone drives on it regularly.
Volume and tonnage calculator →Size compared with other stones
| Size number | Approx. range | Typical use |
|---|---|---|
| #1 | 1 1/2 to 3 1/2 in | Construction entrances, soft ground |
| #2 | 1 1/2 to 2 1/2 in (often up to 3 in) | Driveway base on poor soil |
| #3 | 1 to 2 in | Base layer, drainage |
| #57 | 1/2 to 1 in | Drainage, top layers, concrete |
Gradations come from state highway specifications based on AASHTO sizes, so exact limits vary by state and quarry. Some yards also sell “surge stone” or “shot rock,” which can be even larger. See surge stone.
Common uses
- Construction entrances: a pad of large stone at a job site exit knocks mud off truck tires and keeps it off the street. Many erosion control rules call for large clean stone here.
- Soft or wet ground: large stone bridges over mud better than small stone, which tends to sink.
- Driveway foundation: a bottom layer on clay or wet soil, capped with #3 or #57 and then a dense-graded top.
- Drainage: large voids carry a lot of water, useful in some drains and outlets.
Weight and coverage
At about 1.4 tons per cubic yard, one ton is roughly 19 cubic feet. Because large stone needs a thick layer, plan by depth:
| Depth | Approx. coverage per ton |
|---|---|
| 4 in | about 55 to 60 sq ft |
| 6 in | about 38 to 40 sq ft |
| 8 in | about 28 to 30 sq ft |
A layer should be at least about one and a half to two times the largest stone size so pieces lock together. Use the asphalt base calculator for tonnage.
Placing #1 stone
Spread it with a loader or skid steer, since it is hard to rake. Track over it or use a heavy roller to seat it into the subgrade. On very soft soil, a geotextile fabric underneath keeps the stone from sinking into the mud. Do not expect it to compact like base gravel; it nests but stays open.
Capping it
Driving directly on #1 stone is rough and can damage tires. Cover it with a choke layer of smaller stone, such as #3 or #57, then a dense-graded material with fines for a firm surface. See number 3 stone as an asphalt base.
When not to use it
For a normal driveway on firm soil, #1 stone is unnecessary. Dense-graded base alone works well and costs less to place. Large stone also makes a poor walking surface.
Bottom line
Number 1 stone is large clean crushed stone, about 1 1/2 to 3 1/2 inches, weighing roughly 1.4 tons per yard. Use it for construction entrances, soft ground, and driveway foundations on poor soil, placed at least 4 to 6 inches deep and capped with smaller stone.
Questions people ask
What size is number 1 stone?
Roughly 1 1/2 to 3 1/2 inches, depending on the state specification.
What is number 1 stone used for?
Construction entrances, soft ground, and driveway foundations on poor soil.
Can you drive on number 1 stone?
It is rough; it is usually capped with smaller stone.
How much does number 1 stone weigh?
About 1.3 to 1.5 tons per cubic yard.
Related guides
- Using Number 3 Stone Under Asphalt
- Using Number 2 Stone Under an Asphalt Driveway
- Surge Stone: Using Large Rock to Bridge Mud and Soft Ground
- Number 57 Stone: Size, Weight, Uses, and Coverage
As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.