Gravel driveway - Gravel driveway

[mikec1972]

Was going to use a self binding gravel surface or standard gravel surface to a new rural 3.5m x 30m driveway. The area is a farmers field and mainly sands and gravels so should be fairly free draining. Would we need to use a particular type of sub-base beneath the gravel or self binding gravel surface layer, mindful that there may be some percolation through the top surface? I could use a woven geotextile beneath the sub-base layer to prevent wash down but was wondering if there is a particular grade of sub-base other than type 1 that you would normally use beneath a porous gravel or self binding gravel surface layer?

[seanandruby]

crush and run, or dtp1.