I was told the only difference between fill sand and mortar sand is that the "mortar" sand had been run thru a screen or mesh to get the bigger stones and pebbles out. I am not a mason or in construction, but this is what I was told at the excavating place. Maybe a sales pitch.....anyway I fell for it and bought the more expensive "mortar sand", thankfully when we were raking it out and leveling, we found a 20 year old rusted up chainsaw chain in the sand!:thumbdown:
So much for the screened or meshed sand.
I too wish I'd had put the foamboard down, I am having a terrible time with moles and voles digging under my liner, maybe foam would have helped to avoid this problem for me?