How many cement bag for 20mm thk plaster?

To determine the number of cement bags needed for 20mm thick plaster, first calculate the total volume of plaster required. For example, if you need to cover 1 square meter, the volume would be 0.02 cubic meters (20mm = 0.02m). Assuming a typical mix ratio of 1:6 (cement to sand), you would need about 0.033 cubic meters of cement, which is approximately one 50 kg bag of cement per 1.5 square meters of plaster at that thickness. Therefore, for 1 square meter, you would need approximately 0.67 bags of cement.