Rock first or Sand first

[Downbeach]

I have used egg crate and starboard for this, although I don't use either now, I preferred the starboard.

 

[coralfragscanada]

I'm a firm believer in egg crate first. It gives a firm foundation for structure to be built and spreads out the weight of the rock. It also can be a life saver if you accidently drop a rock or something somehow manages to knock over your rock pile.