After the bricks arc removed from kiln, a minimum period of 1-2 weeks is to be elapsed before they are used in masonry work for avoiding initial shrinkage.
Shrinkage cracks in masonry could be avoided by use of lean cement mortar and by delaying plaster work, till masonry is dried up, after proper curing and has undergone most of its initial shrinkage. In case of structural concrete, shrinkage cracks are controlled by use of reinforcement commonly termed as temperature reinforcement.
Rendering coat of plastering on masonry restrains shrinkage to some extent by its adhesive bond to non-shrinking wall which has already undergone shrinkage. One can thus appreciate the importance of raking of joints in masonry to be plastered so as to give a good key between plaster and masonry.
Sometimes on architectural consideration external walls of building are given on the outside a finish of some rich cement based material like pebble dash or artificial stone. In such cases, in order to avoid shrinkage crack, the finish is divided into small panel of dimensions varying between 0.5 to 1.0 m by providing grooves of 8-10 mm width in both directions.
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