The minimum recommended crushed aggregate base thickness is 4” for most projects. Layers less than 4” thick are possible, however, they do not add much strength to the overall road or compound structure and materials from the underlying sub base or sub grade may contaminate a substantial portion of the layer and inhibit drainage. In addition, they are difficult to compact, they are frequently subject to quantity overruns and it is difficult to construct and maintain smoothness in aggregate layers thinner than 4”. If possible, place your compound gravel after you have installed your system grounding and electrical runs.
Access roads may call out for 1” crusher run gravel for the access road and a compound base of #57 stone. Both aggregates are fairly close in pricing with an average price of $8.43 at the pit. The default pricing used in the road and compound pricing in "My Estimator" includes the cost that would be charged by t he excavating or site development contractor to furnish, deliver and grade the base material.
We recommend that you contact our valued excavators and site development companies to obtain additional information about your project-specific base requirements.