Dry mortar is various powders mixed under dried condition, only need to add water when using on job site, and not allowed to mixed with water in production; The mortar requires a different water ratio according to different function and application of dry mortars, in addition, the ratio of fine powder materials in dry mortar also affect to the water ratio required on job site.

Take cementitious mortar as an example, below is the normal water demand:

water consumption: 24% , for bonding mortar, plaster mortar, and tile adhesive mortar (tile glue mortar).

Water consumption: 28~30%, for gap filler.

Water consumption: 32~36%, for putty.

Remarks: the gypsum mortar water demand is different based on different gypsum.