It is very unusual for cracks to appear on the foundation walls. Cracks signify problems or damage affecting the walls. These problems are mainly caused by shrinkage in the foundation and soil settlement or expansion. Earthquake can also cause cracking. The shape and the size of the crack can be used to establish the cause of these problems. You should, therefore, know the cracks are ‘read’ to determine the severity of the situation. This would also help you when deciding on the action to take.
Any crack which might appear on the walls should be repaired. Concrete might shrink during the curing process. Curing is a chemical reaction and is not necessarily caused by loss of water. The amount of shrinkage on the concrete walls is dependent on some factors which include; type of the concrete used, prevailing temperatures and the amount of water used. Below are the common types of foundation cracks in buildings.
Vertical cracks
These are the thin cracks 
which occur randomly in the foundation walls. Their length ranges from a few inches. The entire wall might also get these cracks. You are more likely to find these cracks in those areas where concrete was poorly or incorrectly mixed the concrete. The lack or use of steel reinforcements also influences the characteristics and degree of cracking in buildings. Shrinkage cracking stops once the concrete curing process is complete.
Cracks in older building
Any crack which might occur in the older building should be taken very seriously. The occurrence of vertical cracks in such buildings can be noticed very easily. Cracking in building indicates that there are more serious problems with the foundation. Cracks which are wider at the top parts of the wall are considered to be more dangerous than the ones occurring at the bottom.
Settlement causes the formation of the wider cracks at the bottom of the buildings. The problem should be addressed to avoid any potential hazards. These cracks should be assessed by a foundation contractor to establish if it is necessary to carry out foundation repair.
Step-like cracks
These are the cracks which form pattern –they are in series of steps. They are mainly caused by settlement, contraction and expanding of soil or the neighboring landscape. Other causes of cracks in
clude the following:
- An inadequate backfill
- Omitted footings
- Shallow footings
- Frost heave
- Water problems
Horizontal cracks
These cracks are considered to be most serious ones in any building. They are mainly caused by expansive soil and improper backfilling. You are advised to contact a foundation contractor once these cracks appear in your building.