#8 Gravel

Number 8 gravel starts as quarried limestone or granite/trap rock that gets mechanically crushed and run through a series of screens to isolate particles between 3/8 and 1/2 inch. This sizing follows the AASHTO #8 and ASTM D448 gradation standards, which is why the material behaves consistently no matter which quarry it comes from. After crushing, the stone is washed to strip away rock dust and fine particles that would otherwise clog its natural drainage voids. The washing step is what separates a true number 8 from unwashed crusher run, which retains fines and compacts into a denser, less permeable surface. The angular shape comes directly from the crushing process, unlike pea gravel, which is naturally rounded by water or mechanically tumbled. That angularity is the reason number 8 interlocks and holds its position in joints, bedding layers, and thin topdressing applications better than a smooth, rounded stone of similar size.

For any load bearing use, number 8 gravel should go on top of a properly compacted sub base, not replace it. Excavate to the needed depth, compact the subgrade, and lay a coarser base material like #57 stone first if the application calls for structural support. Add landscape fabric between the subgrade and the gravel layer to stop the stone from sinking into soil and to block weed growth from below. Spread number 8 in the 1 to 3 inch range depending on the application, then rake it level. For paver bedding, screed it flat rather than compacting, since compaction can create an uneven surface under the pavers. For topdressing or paths, a light pass with a plate compactor helps settle the stone without crushing it further. Skipping the fabric or the base layer is the most common reason number 8 installations shift, rut, or develop mud spots within a season or two.

Compared with #57 stone (3/4 in). Number 57 is nearly double the size and stays looser, which makes it the better structural base under driveways and heavy load areas since it allows more airflow and water movement. Number 8 packs tighter and smoother, so it is the better pick for finished surfaces, paver bedding, and topdressing where looks and footing matter more than raw load bearing capacity.

Compared with pea gravel (3/8 in, rounded). Pea gravel is close in size to number 8 but naturally rounded and smooth, which gives it a softer, decorative look favored for pool surrounds and play areas. Number 8's angular, crushed edges interlock and resist shifting far better, which is why it holds up under paver joints, bedding, and paths where stability matters more than a barefoot friendly surface.

How much number 8 gravel do I need. Measure your area in square feet, decide on a depth in inches, and convert that depth to feet by dividing by 12. Multiply square feet by the depth in feet, then divide by 27 to get cubic yards. A cubic yard covers roughly 100 to 110 sq ft at a standard 3 inch depth, or closer to 130 sq ft at 2.5 inches. Round up slightly to account for settling once the stone is walked on or compacted.

How it is sold and delivered. Number 8 gravel is typically sold by the cubic yard or by the ton, with bulk delivery dropped directly at your driveway, curb, or project site. Since density varies by quarry and moisture content, ordering by the ton gives a more precise weight based estimate, generally 1.4 to 1.6 tons per cubic yard. For smaller jobs like paver joints, it may also be available bagged, though bulk delivery is the more economical option for anything beyond a small patio.