When you see a crack in external wall, any home owner usually tends to think that the material used for constructing the building was of poor quality. This need not necessarily be the reason for crack development in external walls. In our previous article we have seen that crack in external wall due to accumulation of rain water on parapet (chajja) wall.
Low percentage Cracks in external wall is often a complaint with Mumbai residents of high rise buildings. For high rise buildings concrete bricks and blocks / cellular bricks used contain less cement content. Low cement content is another reason for crack development in external walls.
Cement usually shrinks on drying. To avoid shrinkage, a non-shrink acrylic polymer is mixed with cement before application. The non-shrink polymer is available in powder form. Application in this cement can protect the wall form crack development and leakage problems too.
The cracks on external wall-small and big are treated differently. Small cracks can easily be sealed by external surface treatment. Whereas big cracks that would be deep need to be treated with non-shrinking polymer in powder form is used.