Wall cracks can occur in a home for a variety of different reasons. They can occur due to the foundation settling, due to water, due to the mortar or other filler not working, and so on. Most homes and buildings are designed to evenly distribute the weight of the home or the building to ensure that the building is able to move and shift without falling down entirely. Cracks often occur along the bricks that are present and they are going to be different depending on the foundation and the building itself. You may notice this with a basement wall crack.
If you are looking to restore the cracks, you want to make sure that you understand what the issue is and why the crack is appearing in the first place.
The most often cause is that the foundation of the building has shifted according to the moisture level of the ground that the building is on. Heaving from extra water and drought can force the foundation to shift. This is not a huge issue, the way that most buildings are built will be able to shift with the way that the ground is moving. If you have issues, you need to consult a professional for repairs.
