Ultimate Guide to Prevent Cracks in Brick Masonry Construction

Cracks in brickwork can only be prevented by following strict construction materials and practices that do not compromise its quality and performance. Let me mention the guide to follow to prevent cracks in brick masonry construction one my one.

Cracks are mainly created in brick masonry mainly when our construction do not let these brick masonry units to undergo a free movement they are required to. Temperature and other stresses will demand a movement from the brick masonry, which helps to prevent cracks. So most of the steps mentioned below are pro tips to allow desirable movement in brick masonry.

1. Right Mortar for Brick Masonry

The mortar that is used for brick masonry construction must be a weaker mix compared to the mix that is used to make the bricks or block. This is carried out to prevent cracks.

Now, rich mortar mix stronger than the brick limits the minor movements in the brick caused due to temperature and moisture variations that results in cracking of the bricks or the blocks.

2. Time to construct masonry walls

In the case of a framed structure, it is advised to start making masonry walls after the complete frame has been constructed. This let the frame to taken as much as possible loads and deformation occurring during the structural loads. Start the masonry construction after 2 weeks of formwork removal of concrete slabs.

Framed Structure In the Process of Completion. After Which the masonry wall starts.

3. Separation Cracks Between R.C.C and Masonry Joint

The masonry wall is constructed to fill the space created and may have chances to join with entirely dissimilar material like R.C.C columns or beams. Generally, walls joints adjacent column and with the bottom of the beam. These material undergo different expansion and contraction during different conditions which would result in separation crack.

Plastic Mesh Provided Between Masonry Wall and Column Joint

This hence demand a joint at these location using a chicken mesh that overlap 50 mm both on the masonry and the R.C.C member. This must be done before plastering.

Read on: Composition of Bricks in Building Construction

4. Ceiling Loads resulting in Cracks

The ceiling constructed above the masonry walls may be subjected to loads and deflection after their installation. To avoid any effect of these deflection on the masonry wall, the wall must be separated from the ceiling gap using an irrepressible material like non-shrink grouts to avoid cracks in wall. If this is not possible, a chicken mesh can be used on the joint between the wall and the ceiling.

5. Walls Constructed on Floors

When walls are constructed over floor, the floor may deflect due to the loads from the masonry walls constructed. Such loads create, non-continuous bearing which can be only sustained by a robust wall below the floor. To make the walls robust, horizontal reinforcement can be embedded at every alternate courses of the brick. A 6mm diameter rebar is possible.

Image Credits: The International Masonry Institute | Home (imiweb.org)

6. Expansion Joints for Bricks

The use of expansion joints in brick walls divides the wall area into different small segments. Each segment of the wall behave separately from the wall segments. The use of expansion joints allows the brick wall to undergo expansion or contraction depending on the conditions of load , creep, settlement and temperature. 

Expansion joints allows movement vertically and horizontally. This is provided by giving a continuous opening through the brick and filling it a pre-molded foam or neoprene. 

After filling the joint, it is finished with backer rod and elastomeric sealant material to prevent moisture and water penetration into the joint. The joint material must run throughout the full thickness of the brick wall. This prevents clogging of joints with debris and mortar.

Also Read:

1. Top Brick Bonds in Construction
2. Manufacture of Bricks for Masonry Construction
3. What are Fire Bricks?