3/8" Crushed Stone for Indiana Top Courses and Paths

The decision in front of most people reading this has already been half made. The base is in, or it is going in next week, and what is left to choose is the layer that shows. On the southeast flats, where silty ground over a dense fragipan holds water near the surface through winter, and in the river towns on the terraces below the hills, that top layer has to do two things at once: look finished and stay put when the ground under it moves. 3/8" crushed stone is one of the honest answers, an angular material at about 3/8 inch that packs down into a close, even cover.

Choosing the top course once the base underneath is already compacted

Three jobs account for most of it.

A path or patio surface. Screeded and compacted over a prepared base, it gives an even walking surface with a tidy texture and none of the roll you get from a rounded gravel.

Driveway top dressing. On a drive already carrying a compacted dense graded layer, this size fills the open surface texture left by the bigger stone and gives the finished drive a uniform face.

Pipe and utility bedding. Small angular material works in around a conduit or a shallow service line easily and holds its position without needing heavy tamping.

What runs through all three is that it is a finishing material. It is not a base, and it is not a drainage layer.

How a fine crushed stone behaves on fragipan silt and river terrace ground

The fragipan is the local complication. Water perches on that dense layer and sits in the broad flats and valley lowlands, so ground that looks workable on the surface can still be saturated a foot down. A thin stone layer laid on silt in that state will punch down into it, and within a season or two half of what you paid for is below the surface rather than on it. Wait for the flats to dry, and check the spoil: slick ribbons off the shovel mean give it another week.

The second complication is freeze and thaw. Southern winters here are milder than in the north but still cycle repeatedly, lifting and dropping anything sitting on wet silt. A properly compacted base is what absorbs that movement. The top course just rides on it.

Screeding and compacting a thin layer so it does not migrate

Spread it thin. A top course does not want depth, it wants even coverage, so screed to a consistent thickness with a board or a rake rather than dumping and pushing.

Compact damp, not wet. The angular faces key together under a plate compactor and the layer firms noticeably. Sodden silt underneath, though, will pump and smear, and then the compactor is doing harm.

Give it an edge. Without a timber, steel or set edge, a thin surface layer creeps sideways under foot and tire traffic until the middle is thin and the margins are heaped.

3/8" crushed stone next to #89 stone and walkway gravel

The difference between the first two is mostly what is under 3/8 inch. #89 carries fines down to dust and is bought to lock a joint or bed a flag. This size is bought to finish a surface. Walkway gravel overlaps with both but is chosen specifically for how a path feels underfoot.

Yards and tons for a garage apron, a splash pad and a wall that needs something else

Hypothetical layouts. Length times width times depth in feet, divided by 27, then converted with this site's published figure for small chips of about 2,800 lb per cubic yard, or roughly 1.40 tons per yard.

A garage apron top course, 20 feet by 24 feet at 2 inches. 20 x 24 = 480 square feet. Two inches is 0.167 feet, so 480 x 0.167 = 80 cubic feet. 80 divided by 27 = 3.0 cubic yards, about 4.1 tons. The compacted layer beneath is a separate order of #53 stone.

A contained splash pad below a downspout, 3 feet by 8 feet at 3 inches. 3 x 8 = 24 square feet, and 24 x 0.25 = 6 cubic feet. That is 0.22 cubic yards, around a third of a ton. Contain it with an edge, because a downspout discharging onto loose fines will scour them out within a season.

A retaining wall backfill zone, 24 feet long, 12 inches wide, 3 feet tall. 24 x 1 x 3 = 72 cubic feet, or 2.7 cubic yards. This is the case where you should order something else. Backfill behind a wall has to stay open so water can get down to the drain, and a material that compacts tight does the opposite. Use drain rock there instead, roughly 3.7 tons for the same zone.

Where the pile should land on a river terrace lot

Send your own numbers through the stone calculator, which takes length and width in feet, depth in inches, a circle or up to five separate areas, and adds an extra 5 percent by default as margin for topping thin spots. Then choose a date and the tonnage on this page, with delivery set from the ZIP code entered at checkout.

The truck needs firm ground and clear room overhead to raise the bed. On low ground near the river, that rules out most of the yard in a wet spring, so plan the dump point on the drive or an existing hard apron and wheelbarrow from there. If you are weighing this size against the finer path materials for the same job, the comparison is easier with both open in front of you on the product index.