Brick wall crack repair methods
In this construction article, you will be familiar with the proper steps required for repairing cracks in the brickwork to reduce the maintenance and repairing costs significantly as well as to maintain the strength, longevity and safety of the building.
Given below, the detail process for crack repairing :-
Dormant Crack Repairing or Inactive Crack Repairing
Repair the dormant cracks in the wall by slanting the joint and filling with mortar of CM 1:6 that includes synthetic fibres. Dormant cracks are also called inactive cracks or passive cracks.
Also Read : TYPES OF BONDS IN BRICK MASONRY
Active Cracks Repairing
Active cracks occur because of thermal movement. These cracks always reoccur after some time once they are repaired.
- If the cracks remain under 2 mm in width, then the crack can be repaired with the snowfilla paint (ACC make) that is extended in the cracks after it becomes dry. It is recommended to cure painted crack for minimum five days.
- If the cracks remain among 2 mm to 5 mm in width, then the crack should be repaired by injecting the flowing grout in the ratio like cement 1 kg, grout polymer 0.1 kg, and 1-litre water. Bore the hole at a distance of 350 mm c/c for attaching the nipple with the sealant. The grout mixture is injected with the pressure of 3 kg/cm2 through a pressure pump.
- If the cracks remain among 5 mm to 10 mm in width, then eliminate all the loose materials and keep the width of the groove of cracks as 25 mm and depth as 10 mm. Detach the plaster up to a width of 300 mm on the both sides of the cracks and fill the groove with CM 1:3 having 10% polymer by weight of cement. Once the cracks are filled, 12 mm diameter nipples should be inserted at 100 mm c/c and 30 mm to 40 mm deep along the crack line and employ the above grouting method for grouting the cracks.
- Eliminate all the loose materials from the crack and detach the plaster up to 450 mm on both side of the cracks. Fill the cracks with CM 1:3 with 10% polymer by weight of cement.
Repairing of Cracks in Brick Wall (Crack width below 2 mm):
Repairing of Cracks in Brickwork (Crack width among 2 mm to 5 mm):
Repairing The Cracks In Brickwork (Crack width among 5 mm To 10 mm):
Repairing of Cracks in Brick Masonry (Crack width over 10 mm):
To repair wall cracks larger than 1 mm in width, employ the crack stitching method. Secure the M.S clamps of 8 mm diameter bars at 600 c/c after boring through hole in the wall and affix the same with nuts and washers. Grout the clamps with cement slurry grout in the ratio of cement 1 kg, grout polymer 0.1 kg and adequate water to keep the grout flowing. Inject it with the pressure of 3 kg/cm2.
At last, use the first layer of cement plaster of CM 1:2 in 15 mm thickness and second layer of cement plaster 20 mm thick in CM 1:3 in double coat plaster that should be equivalent with the existing surface.
Crack Arrester For Active Cracks
Arrange the RCC band or crack arrester over the line of an active crack to stop the crack and resists reoccurring of cracking.
Crack arrester is provided on both uncovered surface of the wall. The thickness of the crack arrester should be identical to one-third the thickness of the wall.
Crack arrester refers to a vertical composite portion of brickwork and concrete on the basis of the principle of a flitched column. Arrange the reinforcement mesh and fill the cracks in brickwork by applying superior quality concrete. This process should be reiterated on both sides of the wall.
Various types of stitching methods
Stitching methods are applied when broad diagonal cracks happen in brick wall because of the settlement of foundation. When, further cracking occurs, then do the repair by detaching and substituting all cracked bricks. The following types of stitching methods are generally found.
Add precast cement concrete blocks with common size of 250*125*75 mm that is to cast with cement concrete 1:11/2:3 in the first stitching method. Holes are cut to the size of brick having depth 125 mm. The cement concrete blocks are provided into the holes with mortar at alternate layers of brickwork along the line of crack. Once the curing period is completed, the plaster work can be started.
- Insert MS U-shaped dowel bars with diameter 8 mm or 10 mm or as per requirement and with 200 to 250 mm length containing legs of 125 mm. Chase the crack and bore the hole for inserting the dowels bar with legs inside. Make sure that the top of the U remains minimum 20 mm under the brick surface. The cement concrete in the ratio of 1:11/2:3 with 5 mm down grit is used to fill the chase. Once the dowels are inserted, plastering of the surface should be started.
- Insert the RCC stitching blocks of mix 1:2:4 with the arrangement of reinforcement. The length of the block is identical to 1 to 2 bricks, thickness is identical 1 to 2 brick and width identical to thickness of the wall.
Detach and restore the cracked bricks with RCC stitching blocks in every 5th or 6th course or at about 500 mm gapping in the vertical direction of crack length. Substitute the leftover other courses with superior quality ordinary bricks.
Repairing Of Separation Cracks in Brickwork
Separation cracks among column and brick work or beam and brick wall are great concern.
When the separation cracks are found at the juncture of members of two various materials, it should be repaired by filling the cracks with the proper flexible material as mastic compounds.
Secure the chicken wire mesh over the separation crack and re-plaster it to resist the reoccurrence of cracking among the RCC member and brickwork or among brickwork and wooden frame.
Repairing Of Heavy Cracks In Brickwork
Because of the settlement of foundation heavy cracks in brickwork happens. Set the supporting system for the slab and verify weather all the loads are transmitted on the props supporting system. Crush the brickwork partially and then reconstruct.
It is recommended to apply cement concrete of mix in the ratio of 1:11/2:3 with 5 mm grit, when the cracks are larger. The mastic compound can also be utilized for filling cracks in brickwork. Besides, apply the bituminous compound for filling the thin cracks in brickwork when the complication is created for concrete or mortar due to deep self-penetration. It is suggested not to fill the cracks in brickwork with rich cement sand mortar.