Following precautions are to be taken while making use of mortar
Consumption of Mortar
After preparation, the mortar should be consumed as early as possible. The lime mortar should be consumed within 36 hours after its preparation and it should be kept wet or damp. The cement mortar should be consumed within 30 minutes after adding water and for this reason; it is advisable to prepare cement mortar of one bag of cement at a time. The gauged mortar or composite mortar should be used within 2 hours of the addition of cement.
The setting action of mortar is affected by the presence of frost. It is advisable to stop the work in frosty weather or to execute it with cement mortar which will set before it tries to freeze.
In absence of pure water, the sea water may be used with hydraulic lime or cement. It helps in preventing too quick drying of the mortar. However it is not advisable to use sea water in making pure lime mortar or surkhi mortar because it will lead to efflorescence.
Soaking of Building Units
The presence of water in mortar is essential to cause its setting action. Hence the building units should be soaked in water before mortar is applied. If this precaution is not taken, the water of mortar will be absorbed by the building units and the mortar will become weak.
Sprinkling of water
The construction work carried out by mortar should be kept damp or wet by sprinkling water to avoid rapid drying of mortar. The water may be sprinkled for about 7 to 10 days. The exposed surfaces are sometimes covered to give protection against sun and wind.
The mortar should not contain excess water and it should be as stiff as can be conveniently used. The joints should be well formed and the excess mortar from the joints should be neatly taken off by a trowel. The surfaces formed by mortar for building units to rest should be even.