Rip Rap Armor Stone Crushed Stone

Rip rap is large, angular crushed stone you place along slopes and shorelines to stop moving water from washing them out. The pieces run from about 4 inches up to 24 inches or bigger, sorted into size classes so they lock together when stacked. Because the stone's crushed instead of rounded river rock, the sharp edges wedge against each other and hold under wave action or heavy runoff.

The name "rip rap" just means graded armor stone. It says nothing about the rock type, so you'll see it cut from limestone, granite, sandstone, or even recycled concrete depending on what's local. Sizes get called out by class (Class I, II, III on some jobs, or R-3, R-4, R-5 on others), and each class targets a specific median stone size. Bigger classes cost more per ton because fewer pieces make up a load and the driver needs heavier gear to place them.