I want to put in a paver patio behind a short retainer wall I made a couple years ago to level off my yard (10'X15'). It is currently covered by 3" of porous lava rock that breaks down over time (doesn't seem like a suitable base) with fabric beneath it to keep the weeds out. Everything beneath it is dead (no grass roots or weeds)I am in Oregon--lots of rain, not super cold. I don't really want to excavate any more than the lava rock if I don't have to. Everything I read says I need like 4-6" of gravel, but I wonder if I coulg get away with just 2" of sand. The dirt is already compacted, and the area is framed in by the wall. I don't predict any settling, but if I am overlooking something really obvious, please let me know.

Thanks for any advice you might have

--Chris