Which type of gravel do I need?

What is crushed stone? By its simplest definition, “crushed stone” is as basic as it sounds: Stone that has been crushed into smaller pieces.  Most crushed stone is produced in quarries. Instead of being shaped or formed naturally, such as in a riverbed or canyon, crushed stone is produced through man-made processes. So what does this stone-crushing process look like?

It begins with a rock crusher in a place where there are plenty of large rocks, such as a quarry. There are many types of crushers, but their main job is the same: Crush larger rocks into smaller pieces to be used for construction material. 

The crushed stone then goes through different screeners to be organized and stored in different piles according to their size. The screening process starts by removing larger stones, then medium stones, and eventually goes all the way down to the stone dust.

This screening is important because most contractors need specific types of crushed stone to complete different types of projects. For example, you don’t want large stones in ready-mix concrete, and you don’t want stone dust in drainage systems.

After being sorted into different piles depending on the size of the stone, the stone is ready to be shipped from the quarry. Quarries deliver directly to job sites, to concrete plants, or to wholesale distributors who sell the stone through retail to customers.

You can even purchase bags of stone, whether it is for construction or decoration, from Lowes and Home Depot.

Has crushed stone always been used widely for construction?

Actually, no.

Crushed stone did not become a staple in construction until after World War 2 when inventors created the equipment needed to crush and move stone efficiently.

Because large stones and quarries are hard on tires, crushed stone was challenging to make and transport until heavy machinery with tracks arrived on the scene. WW2 expedited the development of this type of machinery, and crushed stone began to be used widely in construction projects in the 1940s and 1950s.

What is gravel? Gravel is similar to crushed stone because it is a type of rock, but these two materials don't occur in the same way. While crushed stone is a product of human manufacturing, gravel occurs through natural processes. A geological definition of gravel is “a natural material that consists of water-transported materials and usually has a rounded shape as a result of the water transport.” One of the key differences in the look and feel of crushed stone and gravel is the edges of the stone.

Crushed stone often has an angular and jagged edge because of the crushing process. Gravel, on the other hand, typically has a very smooth texture and surface because of the natural weathering and wear of being exposed to running water. Crushed stone often has an angular and jagged edge because of the crushing process. Gravel, on the other hand, typically has a very smooth texture and surface because of the natural weathering and wear of being exposed to running water.

Types of Gravel/Stone and their Typical Usage

Crusher Dust - Fine Particals, easy to level, typically used for levelling patio pavers or traction on ice.

Crusher Run - Comes by many names depending on the size and grain distribution.  Typically used when a structural base is required like a driveway, walkway or under concrete and or a retaining wall.

Clear Stone - Crushed stone that has been screened of all fine materials other than its specified size ex. 1 inch clear stone.  Used behind retaining walls, french drains, foundation drains or anywhere drainage is required.  The larger the stone the larger the void.

Beach Stone/Pea Stone - Made by the natural errosion process and screened to a particular size ex. 2 inch beach stone

Surge Rock - Large rock typically 4-6 inches.  Depending if it is "dirty or clear" may mean its good for compaction or drainage.  Usually used in heavy duty applications.