#4 Stone vs Fill Dirt: Size, Cost, and Which to Use

#4 Stone

Sieve size #4 in the ASTM aggregate grading means most of the stone passes a 1.5-inch screen and stays on a 3/4-inch screen. In practice you get a pile of roughly walnut to golf ball sized rock. Every piece is angular because it was crushed, and those sharp edges lock together under load instead of rolling like river stone. Because it is washed or screened clean, there are no fines to fill the gaps between pieces. That is the whole point: about 35 to 40 percent of a pile of #4 is air, so water moves through it fast.

Fill Dirt

Subsoil material free of organic matter, used for grading, filling, and raising elevation. Fill dirt is a lower-grade soil that lacks the nutrients of topsoil, making it ideal for structural and non-growing applications where settling must be minimized.

#4 Stone

• ✓ Driveway and road base
• ✓ Drainage beds
• ✓ Retaining wall backfill
• ✓ Construction entrance pads
• ✓ Pipe bedding for large pipe
• ✓ Erosion control

Fill Dirt

• ✓ Grading
• ✓ Filling depressions
• ✓ Raising elevation
• ✓ Backfill
• ✓ Construction site prep
• ✓ Under slabs

#4 Stone

• + Excellent drainage with 35 to 40 percent void space
• + Bridges soft ground better than smaller stone
• + Cheap, $20 to $40 per ton, and stocked everywhere
• + Angular pieces lock together under load
• + Same price as #57 with more drainage capacity

• − Too coarse to walk on or drive on as a surface
• − Needs a finer cap layer for any traffic
• − Hard to rake and spread by hand
• − Sinks into soft clay without fabric

Fill Dirt

• + Very affordable — often cheapest material available
• + Compacts firmly for structural support
• + Does not decompose or settle like organic soil
• + Widely available from construction sites
• + Ideal base under gravel or concrete

• − Not suitable for growing plants
• − Must be free of debris and contaminants
• − May contain clay that drains poorly
• − Needs compaction in layers for stability
• − Quality varies widely between sources

#4 Stone

#4 stone is crushed rock screened to pieces between 1 and 1.5 inches, with some quarries running it up to 2 inches. It is angular with sharp fractured faces. Color follows the quarry: gray or blue-gray limestone in the Midwest and Northeast, gray to pink granite in the Southeast, tan limestone in Texas.

Fill Dirt

Fine to coarse soil particles, free of organic matter like roots, grass, or leaves. Color ranges from tan to reddish-brown depending on local geology. "Clean fill" means free of debris, rocks larger than 3", and contaminants.