Gabion rock fill should be hard, durable, dense and non-frost susceptible, with a dimension of 4-8 diameter. A block shaped rock will be easier to install, and produce a better finish than a rounded cobble shaped rock. To maximize the mass of the structure, it is necessary to minimize the void volume of the fill within the gabion unit. i.e. more rock, less air. We do not recommend that smaller rocks be used as they will fall through the apertures in the mesh. However, there are certain specific circumstances when smaller rock can be used. The range in sizes may allow for a variation of 5% oversize and/or 5% undersize rock, provided it is not placed on the gabion exposed surface. Our Product Installation Guide for gabions provides further detail.
Gabion rock fill is generally supplied by the ton. Depending upon the density of the rock fill at your local quarry, the final tonnage you order will vary. As a rule of thumb, gabion rock fill is going to be around 1.4 -1.5 tons per cubic yard. This would allow for overfilling of units and some wastage. It assumes that the gabion is 25-35% voids, and that the density of good rock fill is 155lb/CUft.