Is Your Wall Cracking? Here's What You Need to Know

Are you tired of dealing with unsightly cracks in your walls? Cracks not only ruin the aesthetics of your home or building but can also indicate serious structural issues. Whether you're a homeowner, builder, or engineer, understanding the causes of wall cracking is crucial to prevent future damage and ensure the longevity of your structure. 

The occurrence of wall cracks occurs in different ways but certain typical modes and characteristics exist for these. The cause of cracks can be clearly understood from the type and the magnitude of the cracking.

In this article, we'll delve into the various causes of wall cracking, from poor construction practices to temperature changes and foundation issues. So, get ready to become a crack detective and uncover the secrets behind wall cracking!

Causes of Wall Cracking

The main reason behind the formation of cracks in the walls is deformation. These deformations occurred may be at the macroscopic level or at the macroscopic level. Here different deformations as different causes of crack formation are explained below:

1. Deflections in Slab or Roof Elements
2. Differential changes due to temperature changes and stresses
3. Roof Expansion and Construction
4. Cracking due to Creep and Shrinkage
5. Poor Detailing and Improper Construction
6. Load Bearing Parameters
7. Foundation Factors
8. Settlement

Deflections in Slab or Roof Elements

Cause: Cracks can be developed in the wall slab interface, where the wall supports the slab. This is caused due to the rotation of the slab (supported by the wall) under the action of load over it. This rotation of the end of the slab will result in the upward left tensile force, which is the reason behind the crack formation. This type of crack is more visible on external walls than on internal walls.

If the induced tensile stress at the outer surface is greater than the permissible stress of the wall, the crack formation will be there. 

Remedy: These types of cracks can be accommodated only by the incorporation of the tensile reinforcement that is sufficient to handle the tensile stress. Another option is to separate the slab from the walls. A third way is to increase the stiffness of the slab so that the slab deflection can be reduced. But in practice, zero deflection is not possible.

Differential Changes due to Temperature Changes and Stresses

Cause: Differential expansion characteristics can be shown by two walls or a wall or column with a different modulus of elasticity that will result in differential strains. These strains can be caused as a result of different stress levels for the wall of the same material. The external walls are subjected to temperature changes that are the main reason for temperature stresses and strain and hence crack is formed. These will bring cracks in the connecting walls.

Remedy: Choose materials that can resist such strains for internal and external walls. Also, the materials and design bear the stress level during the construction of higher buildings.

Expansion of Roof and Its Construction

Cause: When compared to the foundation structure, the roof is subjected to high-temperature changes. The walls too are exposed to direct sunlight will results in a small amount of deformation. The relative movement of the roofs and the walls are reflected as stresses in the wall section. When these stresses exceed the permissible value, long horizontal cracks are formed. This crack formation is a sure case to occur unless we provide provision for an independent movement.

Remedy: The main remedy under such situations is to provide a design that could facilitate such types of movements.

Creep and Shrinkage Cracking

Along the edge or at certain points of the masonry walls, restraints are provided. Stresses are developed in these areas when differential shrinkage has occurred between the masonry and the restraining media. In some situations, long-time creep may be the source of stress and related movements.

Poor Details and Improper Construction

Poor construction includes:

• The wrong location of the control joints
• Window Alignment
• Placement of steel plates above the opening
• Design of drain
• Location of Splices

Remedy: The usual procedure is to place the control joint first over the mortar. Only after this hardens, the raking is carried out for a depth of 20mm. This remaining mortar is the packing of the caulking. 

• The issues of spalling can be reduced by taking care of the run-off drains for the roof. This is caused due to the freeze-and-thaw action. The water falling over the wall will result in spalling.
• The windows opening will have a plane of weakness on either side of the opening. If the window opening is placed above another, proper alignment must be done for the sides of the opening.
• Spalling due to eccentric load can be prevented by placing a steel plate above an opening.
• The use of Joint reinforcement will result in fine cracks instead of large single cracks. Special care must be taken while splicing is done.

Load Bearing Factors

It is necessary that the designer decide whether the wall is load-bearing or non-load-bearing. The load-bearing walls will resist the crack formation by means of a clamping action. This increases the shear friction between the unit and the mortar joint. If not, here comes another reason for cracks in walls due to overload on it.

Foundations Issues and Settlement

Issues of cracking emerged may be found in masonry wall construction over a concrete foundation. The thermal expansion of the walls will work against the drying shrinkage of the concrete. This will create the extension of the masonry wall beyond the foundation. 

During a lower temperature, the masonry wall will contract and the tensile strength of the same will not be sufficient to keep the masonry wall back. This will result in cracks near the corners.

The settlement of the foundation is one of the main reasons behind the formation of cracks. This is mainly experienced in structures supported in soil or silty clay soil. The detrimental settlement is caused by structures whose foundations are built based on a guess ( small construction). 

The cracks due to the settlement are observed larger at the top and they will diminish as hairline cracks at the bottom. This is based on the relative direction of the settlement and the location with respect to the length of the wall. One must keep in mind that the differential settlement is the main issue, not the total settlement.

Remedy: The foundation issues and settlement are the two major issues that would result in serious wall cracking. The diagnosis demands an expert investigation of the cracks and expert remedy and rehabilitation for the complete stability of the structure. Most foundation and settlement issues can be resolved by the underpinning process. 

It is essential to determine the underlying cause of wall cracking before attempting to repair it, as the repair method will depend on the cause. In some cases, minor cracks can be repaired with simple methods such as patching or sealing, while more significant structural issues may require more extensive repairs or even rebuilding. It is advisable to consult a professional for a thorough evaluation of the situation and recommendations for appropriate repairs.

Also Read: How to Repair Interior Plastered Masonry Walls?