Cracks in brick walls are the result of many different factors, from simple accidents to subsidence or earthquakes. When a brick walls cracks, it is important to assess and repair the damage early on, so the problem does not have a chance to damage the structural integrity of the wall.
Clean the cracked area and the surrounding wall by brushing it with a small brush to remove any dirt and debris. Scrape any damaged brickwork and mortar from around the crack using a chisel. Spray compressed air into the crack to dislodge any deep-set dirt, then brush the area again with the small brush.
Prepare the cement bonding agent according to the instructions supplied by the manufacturer. Either pump the bonding agent into the crack or apply the agent into the crack using the end of a trowel. When applying the bonding agent, be sure to make an even line from one end of the crack to the other with a three-quarter fill. An even line is one that contains an even amount of agent throughout.
Push the stainless steel crack repair rod into the crack and push it into place with the chisel, so it is completely immersed in the bonding agent. Allow the agent time to set. Prepare your mortar, paying careful attention to the manufacturer's instructions. Apply the mortar to the crack, ensuring that it gets deep into the crack at each point. Smooth over the surface with the trowel. Allow the mortar time to set.
For the best possible finish, be sure to use mortar that is the same colour and texture as the original mortar or as close as possible to the original. This will ensure that your wall has as close to a uniform finish as you can get and that your repairs will not detract from the overall appearance of the brickwork.
Avoid the temptation to simply patch the cracks with mortar if the crack is active, meaning it is increasing over time. Patching the crack does not address the underlying problem causing the crack, therefore the crack will return eventually. To avoid further damage to the wall, reinforce it with a steel rod inside the new mortar. This increases the strength of the wall over the damaged area.