Question for you expert retaining wall guys. What is NCMA specs for backfilling a retaining wall? There is a wall approximately 8' in height going up around my area by another contractor where it's being backfilled with 411( 2" less with screenings) or what some guys call modified 2-A and compacted. I always thought it was spec to backfill with clean 57's and compact for proper drainage. I've always been taught to use clean 57's. Can walls be backfilled with 2-A and compacted or is this guy asking for a blowout???? I'll try to snap some pics later today.