For a job i am doing i need to raise 3k sq feet 2 feet. 2000 sq feet of that area will be patio. Now why is it neccessary i use road base for this. Why can't i just import clean fill and compact with a bomag trench compactor? Isn't dirt compacted a 95% the same as stone at 95%? Please explain to me why this can not be done??? I am building a 2 teir retaining wall right now where the 2nd teir is built on compacted imported fill. The engineer okayed this. So why is everyone always using stone to build areas up?