ledgeman

/ˈlɛdʒmən/
noun
  1. A worker who assists a stonemason, especially one who prepares or carries stone and mortar.
    • The experienced ledgeman knew exactly how much mortar to prepare for each section of the wall.
    • The ledgeman carefully mixed the mortar while the mason shaped the stone.
    • As a ledgeman, he spent most of his day hauling heavy blocks to the scaffolding.