White stains in the walls and cracks in the walls

Dear murlidhar

  1. In the newly constructed wall there are two main reasons for white stains, one is presence of salt in the bricks and other is due to salty water used in the masonry work. After curing work completed then let the wall to dry .When wall fully dried than all the salt in the form of white stain comes out than rub it with brush or with hard broom and clean it fully. Wash the wall with water (but it should not be salty water).

2. This crack is due to not providing proper slip to the RCC slab on the wall by not providing bearing plaster on the wall before laying the slab. For repair

The plaster should be removed from cracked portion. The joints should be widened at least 20 mm to 25 mm in thickness. Clean old material by washing and brushing.

Apply slight cut on edges in straight line to provide neat joint. Make the surface damp 24 hours before application of new plaster.

Cement mortar should be applied on defective portion. Make 20 mm wide and 25 mm thick groove at the junction of the slab and wall.

Keep the surface wet at least for 3 days. When surface is dry, finish it according to adjacent area on wall.  For more detail visit gharexpert construction section safety where crack articles give more information about repair.   Link is given below.

http://www.gharexpert.com/articles/Cracks-1468/How-To-Repair-Cracks_0.aspx

Thank you very much sir, for the useful reply.