There are 4 primary causes of defects in brick masonry work. These are as follows.

sulfate attack
crystallization of salts from bricks
Corrosion of Embedded Iron or Steel
shrinkage on drying

Table of Contents

1. sulfate attack

Common forms of defects caused by sulfate attack are:

cutting and falling bricks and
Formation and rendering of cracks in joints

These types of defects occur when sulfate salts present in the brick work

react with alumina of cement in case of cement mortar or
React with hydraulic lime in case of lime mortar

This reaction causes an increase in the amount of mortar and results in cracks, chipping and chipping in the brickwork.

These defects are usually found in the following condition;

exposed boundary wall
parapet wall
Manholes and retaining walls (where they are exposed to moisture)

Such defects can be prevented by adopting suitable construction details and good quality material which prevents the penetration of moisture into the brick work body.

2. crystallization of salts from bricks

Brick flow - defects found in bricks — brick bloom

The defect formed due to crystallization of salts from brick is called upfluorescence.

The presence of highly soluble salts in the brick is the primary cause of this type of defect. When these bricks come in contact with water, the soluble salts present in it dissolve and come to the surface in the form of a white powder.

Due to this defect the wall looks dull and loses its beauty.

The only way to correct this defect is to frequently brush and wash the surface of the wall.

3. Corrosion of Embedded Iron or Steel

The formation of cracks in brick making falls in this category.

Moisture in the building causes corrosion of embedded iron or steel. Corrosion of steel increases the volume of the metal and causes cracking of the brickwork.

Defects caused by corrosion of steel or iron can be prevented by encasing the reinforcement in a thick and impermeable cement mortar and providing a 15 to 25 mm casing around the embedded member.

4. shrinkage on drying

Cracks in masonry joints are a form of defect caused by shrinkage.

Since brick is a porous material, it has a tendency to absorb water. When it absorbs water it swells and when this absorbed water evaporates the brick begins to shrink. This shrinkage of the brick causes cracks in the brick masonry joints.

The formation and type of crack depends on the type of mortar used in brick masonry. Where lean mortar is used in brick masonry, the cracks are distributed over a large number of joints and where coarse mortar is used, the cracks are few but wide.

Shrinkage cracks do not affect the structural strength of the brickwork and can be easily prevented

By using good quality brick and mortar
protecting masonry from moisture