Causes of plastering defects and proper remedies

Lack of hardness

The plaster should contain good strength but the plaster becomes soft because of the following reasons:

  • Inadequate cement.
  • Application of sand with unnecessary quantities of dust (above 15% by mass passing the 0,075mm sieve).
  • Application of a mix with weak water-retention properties.
  • The inclusion of excessive water for a long period once the first mixing is made (a practice called as re-tempering).

It is recommended to use a slightly weaker plaster as it is prone to less cracking or debonding, as compared to strong plastering.