PVC floor (dry bottom floor) pre-installation precautions:

Update:27 Aug 2018

The following requirements are for different horizons: […]

The following requirements are for different horizons:
Cement floor: thoroughly clean the PVC skirting board  before construction. The floor level must be clean and not wet (if it is painted, it must be dried after the paint is dried). If there are irregularities or other defects, all cracks and holes should be removed. Fill or smooth with a suitable filler such as gypsum. When the ground is heavily sanded, it should be repainted.
 Remove all dirty oiled or waxed floors. Do not lay on a soft plastic or rubber floor. This floor must be removed or covered with a plywood and suitable for all cracks and holes. Fill the filler (such as gypsum).
Note: Do not lay dry floor on:
Frequently hot on the ground
Ground with too high or too low temperature
Wood chip board
Frequently wet place