What are the reasons for cracks in plastering works? What are the remedies? Does the thickness of plaster have any role with cracking?

Some reasons of cracks are:

• Non structural cracks as result of overtrowelling a rich mix.
• Structural cracks caused by differential movement of the foundations, moisture expansion or drying shrinkage of masonry units, or thermal movement of the roof.
• Debonding.
• the hardness or strength of plaster. 

Of course the thickness of plaster may cause cracks.

The thickness of plaster may cause cracks, Poor workmanship and curing.

the hardness or strength of plaster.

plastering is occur

crack in plaster

the most reason is the difference in the expansion factor

as the thickness of plaster rise the possibility of cracks to occur rise

Structural damage also occurs as a house settles and moves in place or because of the expansion and contraction of the wooden lath holding the ceiling in place, due to moisture in the air. The final major causes of cracks in plaster ceilings are poor workmanship and improper curing of the plaster.

Hardness and strenght pf plaster,debonding,drying shrinkage of mansory units

stress of settling 

poor workmanship

because of exapnsion 

not proper curing

High silt content in sand (more than allowable) and lack of proper curing can also be causes of cracks in plaster.

Concretes, plasters are mainly the same in components and cracks are always there due to its mix proportions, poor workmanship and poor curing methods. Here are some remedies that would help to minimize cracks: 1) for thick plasters, put wire mesh (half inch opening) on the area to be plastered and fasten it with concrete nail. It will be its reinforcement. 2) The curing method: cover the plastered area with polyethylene sheets to retain moisture in longer time. Spray water regularly (5 to 6 times a day for 2 to 3 days). 

mainly two reason for crack in plastering occur.  first is mixing of mortar means ratio of cement sand and water. another one is thickness of plaster.