For 15 mm thick cement plastering 1 : 6 on 100 sq. m. new brick work, the quantity of cement required is

The volume of the plaster = 100 m2 × 0.015 m = 1.5 m3

We have to increase the mortar value by (To accommodate new wall depression & wastages volume of plaster)

Increase mortar for uniform wall by 30-35%

For volume of dry mortar increase 25%

So, it is possible to go around 60% extra volume for dry & wet mortar.

Therefore, volume of dry mortar = $(1.5 \times \frac{{160}}{{100}} = 2.4)$

Now 1 part is of cement has 6 part is of sand so,

Cement = (1/7) × 2.4 = 0.343 m3

1.5×1.54×1/7=.33