At least three days after plastering cement mortar, finish coat is knocked to check its cohesion with concrete and parts with dead sound shall be plastered again.

• 抹上水泥砂浆，至少经过三天后，用敲打法检查抹面层与混凝土结合程度，发现哑音时，必须将该部分打掉重新抹浆。