As a homeowner or property manager, it’s essential to know how to fix structural cracks in walls to maintain the safety, integrity, and value of your property.
Structural cracks pose a significant risk, and if left untreated, they can lead to severe damage and even collapse.
In this comprehensive guide, we will explore the causes, identification, and various methods for repairing structural cracks in walls.
How to Fix Structural Cracks in Walls
Causes of Structural Cracks in Walls
Understanding the root cause of structural cracks in walls is crucial for determining the appropriate repair method. Some common reasons for cracks in walls include:
Foundation movement is one of the primary causes of structural cracks in walls. This can occur due to soil settlement, soil shrinkage, or expansive soils that cause the foundation to shift or heave.
Extreme changes in temperature can cause materials to expand and contract, leading to cracks in walls. This is particularly true for masonry walls, which are more susceptible to temperature-related cracking.
Certain chemical reactions, such as the corrosion of steel reinforcement in concrete walls or the sulfate attack on masonry, can lead to cracks in walls.
Poor Construction Practices
Inadequate construction practices, such as insufficient compaction of fill material or improper placement of reinforcement, can also lead to structural cracks in walls.
Earthquakes, floods, and other natural events can cause significant stress on building materials, leading to cracks in walls.
Identifying Structural Cracks
Before learning how to fix structural cracks in walls, it’s essential to identify the type of crack you’re dealing with. Cracks in walls can be categorized into three primary groups:
- Active – cracks in masonry that are increasing in width and/or length
- Passive – cracks in walls that are not increasing in width or length
- Cyclic – cracks in brickwork that open and close seasonally
To determine the appropriate repair method, monitor the crack over time to identify its cause and behavior.
Generally, passive or cyclic cracks less than 5mm in width can be repaired using simple techniques, while active cracks or those greater than 5mm in width should be addressed by a structural engineer.
Repair Methods for Structural Cracks in Walls
There are several methods for fixing structural cracks in walls, depending on the type and extent of the damage.
Some common repair techniques include:
Crack stitching involves bonding twisted stainless steel rods into the wall across the cracks at regular intervals.
This method strengthens the masonry and allows the cracked wall to behave as a reinforced, non-fractured unit.
Crack stitching is ideal for passive or cyclic cracks less than 5mm in width.
Installation of Crack Stitching Bars
- Cut horizontal channels in the masonry, typically in the bed joint where installation can be easily disguised.
- Flush the slots with clean water to remove loose material and prevent porous brickwork from absorbing moisture from the grout.
- Fill the slots with a high-performance, shrink-compensated cementitious grout, leaving room to repoint and match existing finishes.
- Push the crack stitching bars into the slot, ensuring they are fully encapsulated in the grout. The bars must extend 500mm on each side of the crack to absorb and disperse loads evenly into the wall structure.
- Make good to disguise the slot and ensure all cracks are filled and sealed to prevent water ingress.
Epoxy injection is a method used to repair cracks in concrete walls.
The epoxy resin is injected into the crack under pressure, filling the void and bonding the concrete back together.
This method is suitable for repairing active cracks in concrete walls, as it provides strong adhesion and prevents further movement.
Underpinning is the process of strengthening and stabilizing a building’s foundation to address foundation movement.
This method involves excavating underneath the existing foundation and constructing new, deeper footings or piers to support the structure.
Underpinning is a suitable method for fixing structural cracks in walls caused by foundation movement.
Grouting is a technique used to fill voids or cracks in masonry walls.
Cementitious or chemical grout is injected into the wall under pressure, filling the voids and stabilizing the masonry.
Grouting is suitable for repairing passive or cyclic cracks in masonry walls.
Carbon Fiber Reinforcement
Carbon fiber reinforcement is a method used to strengthen and stabilize masonry and concrete walls.
Carbon fiber sheets are bonded to the wall surface, providing additional tensile strength and preventing further cracking.
This method is suitable for repairing active cracks in masonry or concrete walls where additional reinforcement is required.
Choosing the Right Repair Method
When deciding how to fix structural cracks in walls, it’s essential to consult with a structural engineer who can assess the damage and recommend the appropriate repair method. Factors to consider when choosing a repair method include:
- The cause of the cracks
- The type and extent of the damage
- The type of wall material
- The desired aesthetic outcome
Preventing Structural Cracks in Walls
Prevention is always better than repairing when it comes to structural cracks in walls.
To help prevent cracks from forming, consider the following steps:
- Ensure proper construction techniques are used during the building process
- Regularly inspect and maintain your property
- Address any leaks or drainage issues promptly
- Ensure appropriate insulation and ventilation to minimize temperature fluctuations
Hiring a Professional
While some minor cracks can be repaired by homeowners, it’s essential to hire a professional for significant structural damage.
A structural engineer or experienced contractor will be able to assess the damage, determine the cause, and recommend the appropriate repair method.
Cost of Repairing Structural Cracks in Walls
The cost of fixing structural cracks in walls can vary widely depending on the extent of the damage, the repair method chosen, and the location of the property.
However, it’s crucial to remember that the cost of repairing structural cracks is often much less than the potential long-term damage if left untreated.
Maintaining Your Repaired Walls
Once you’ve learned how to fix structural cracks in walls and completed the repairs, it’s essential to maintain your walls to prevent future issues.
- Regularly inspecting your walls for signs of new cracks or damage
- Addressing any leaks or drainage issues promptly
- Ensuring proper insulation and ventilation to minimize temperature fluctuations
Knowing how to fix structural cracks in walls is essential for maintaining the safety, integrity, and value of your property.
By understanding the causes of cracks, identifying the type of crack, and choosing the appropriate repair method, you can effectively address and prevent structural damage.
Always consult with a structural engineer or experienced contractor to ensure the correct repair method is employed, and maintain your walls to prevent future issues.