Cracks in the walls are a very common issue in all types of buildings. Many people wonder ‘What causes cracks in the walls?’ In fact, there are several reasons for cracks in walls. It can be due to structural issues caused by the contraction and extraction of the materials used in construction. Or simply a minor problem like hairline cracks. These can be fixed by using fillers and paints.
These cracks can vary in size, depth, and patterns, mainly because of factors like settling, structural stress, and more. Read on to learn more about wall cracks and how to repair them.
Major Types of Cracks in Walls
The following are different types of cracks in walls with their respective causes:
Vertical Cracks
Vertical cracks are typically straight hairline cracks, though they can become slightly wider. Concrete must be prepared using the proper techniques and materials to avoid this.
Causes of Vertical Cracks:
- When plaster expands during drying, it can lead to shrinkage. This is due to humid conditions. This can be fixed using paint and filling.
- Vertical cracks are also caused by foundation settling. This is due to the soil movement, which can affect the support of the building. This needs serious attention.
- The seasonal changes can cause the soil to expand and contract. It can result in flooding and lead to cracks in the walls.
Horizontal Cracks
The horizontal cracks are an indication of a wall failure. This needs proper immediate attention.
Causes of horizontal cracks:
Poor soil
Wet or dry clay-rich soil has the feature of expanding and contracting. This causes pressure on the foundation walls, which can lead to cracking.
Hydrostatic pressure
The excess water occurs due to poor drainage. This affects the foundation of the building and builds pressure. This pressure causes cracks in the foundation wall.
Chemical reaction
A chemical reaction includes the corrosion of metal. It can alter the structure of the walls, causing cracks over time.
Diagonal Cracks
Diagonal cracks are often referred to as shrinkage cracks due to the concrete’s contraction during the curing process.
Causes of diagonal cracks
Structural deterioration
Diagonal cracks often occur in concrete due to its shrinkage. This is also called a shrinkage crack. Poor soil conditions during construction can lead to such issues over time.
Brick walls
When stress distribution is uneven in brick walls, diagonal cracks form. These are load-bearing tracks and can commonly occur near windows or doorways.
Reasons for Cracks in Walls
Foundation Settlement
If the soil underneath a structure fails to support the building’s weight, cracks less than 1.5 mm thick may appear. Stabilising the structure using appropriate methods can prevent these cracks. This is seen as vertical or diagonal cracks in the windows or doors.
Thermal Expansion and Contraction
Temperature variations cause thermal expansion in concrete. When there is a change in the moisture content of the air, it leads to temperature variation. Expansion or contraction occurs in these materials. Expansion is due to heat, and contraction is due to the cooling effect. This can lead to stress on the walls. Usually, hairline cracks appear in a horizontal or stair-like pattern.
Moisture Infiltration
Flow of water or moisture fluctuation can result in cracks in the building. Water flowing into the building material can cause it to expand. Water intrusion can weaken material strength, and when moisture evaporates, gaps can form, leading to issues such as bulging, peeling paint, and mould growth.
Poor Construction Practices
When the materials used in the construction, like sand and cement aggregate, are poorly mixed, it causes cracks. Proper load support design, including adequate steel reinforcement, is critical; inadequate support can lead to cracks. Other factors include improper curing, low-quality materials, and poor workmanship.
Soil Shrinkage
The movement of soil can cause high stress on the foundation of the construction. Its expansion and contraction with changes in weather conditions can cause cracks in the walls.
Vibration and External Forces
Vibration caused by heavy machinery, nearby construction, and traffic can cause external forces. These forces lead to the creation of stress and tension on the building walls. It results in developing cracks over time.
Load-Bearing Issues
The load-bearing walls, such as pillars, need adequate support. When there is an excessive strain or inadequate support, it can lead to poor load bearing. This causes cracks where walls meet ceilings as a sign of load-bearing issues.
Seismic Activity
The regions that are prone to earthquakes affect the building. It has increased stress, which results in cracks in the walls. Buildings in such places must be designed to withstand these seismic forces.
Improper Curing of Concrete
Curing is a process that occurs in the preparation of concrete. If the concrete does not dry and harden properly, it has a high risk of developing cracks. It fails to provide the necessary strength and durability that the concrete requires.
Plumbing Leaks
Water leakage from pipes and drainage systems can cause structural damage. If water leaks between the concrete particles, it can weaken the material’s strength. This results in cracking of the walls.
Lack of Maintenance
Negligence and improper maintenance of construction can lead to crack occurrences. Filling the cracks and gaps with paint and adequate material is essential. Addressing the moisture issues will help prevent cracks.
Structural Overloading
A building must be designed according to its capacity. Overloading the construction can result in cracks in the walls. For example, shifting from residential buildings to commercial use can be inadequate.
Overloading of Floors
The excessive weight, more than the building can hold, leads to increased stress on the lower walls, which results in cracks. Upper floors, which are excessively weighted, cause increased pressure on the building.
Wind Loads
High winds can cause pressure on the building. Any construction near windmills or the seashore can experience high tide winds. This causes increased tension on the surface of the walls. It results in introducing cracks.
Differential Thermal Movement
The expansion and contraction that occur in different buildings at different rates also result in a variation in the temperatures. The joints of the building can cause movement between the different materials used for construction.
Chemical Reaction
Chemical reactions have a severe impact on the walls of the building. The highly reactive chemicals can cause expansion and cracking of the walls. This can be a high risk to the building structure and its quality.
Poor Installation of Doors and Windows
Proper workmanship when installing doors and windows during construction is important. The corners of windows and doors are more prone to crack occurrence. These are places where stress is more concentrated and requires proper attention.
Inadequate Waterproofing
Always notice that the walls have adequate waterproofing. The walls are more prone to water-related damage due to moisture infiltration, which can lead to the cracking of the walls.
Effect of Cracks in the Walls
- The cracks indicate that there is structural damage, which is an underlying problem. For example, foundation problems can affect the strength of the construction.
- Visible cracks can make the building look less attractive, reducing its aesthetic value.
- Cracks in the building can also reduce the property’s market value. The reasons are an indication of poor construction. Pests in the building can also lead to structural cracks.
Identify Your Wall Crack: Is It a Minor Fix or a Major Problem?
Cracks in walls and ceilings are common in homes, but not all of them mean the same thing. The size, shape, and location of a crack help determine if it’s just cosmetic or a sign of a more serious issue.
Minor or Cosmetic Cracks
- Small, thin cracks (often called hairline cracks) are usually less than 2–3 millimeters wide.
- Commonly found near plaster joints, paint layers, or where building materials expand and contract.
- These cracks are usually caused by normal drying, humidity changes, or minor settling of the house.
- Quick fixes such as wall putty or filler, followed by repainting, are enough.
Serious Structural Cracks
- Cracks wider than 5 millimeters, especially if they are diagonal, horizontal, or near doors and windows, can indicate a structural concern.
- Large or deep cracks may point to:
- Foundation movement or soil settlement
- Stress on columns, beams, or load-bearing walls
- Water damage is weakening the plaster or concrete
- Such cracks should be assessed by a structural engineer or building professional.
When to Call a Professional: Your Structural Health Checklist
You need to call a professional if you observe these warning signs:
- Crack Width Over 5 Millimeters: Cracks wider than 5 mm (about the thickness of two stacked coins) are concerning and often indicate movement or settlement issues in the foundation or structure.
- Diagonal or Horizontal Cracks: Cracks running diagonally, horizontally, or stair-step patterns around doors, windows, or walls suggest foundation settling or structural stress that needs professional evaluation.
- Cracks That Grow or Multiply: If cracks widen, lengthen, or increase in number over time, it means ongoing structural movement that can’t be ignored.
- Clusters of Cracks in One Area: Multiple cracks close together can indicate widespread structural issues, such as soil movement or water damage.
- Cracks Accompanied by Other Problems: Doors or windows that stick or don’t close properly, uneven or sagging floors, bulging walls, or visible wall displacement signal deeper problems needing immediate expert assessment.
- Sudden Appearance After Environmental Changes: If cracks appear suddenly after heavy rain, drought, or seismic activity, they could be linked to foundation shifts or soil expansion/contraction.
How to Repair Cracks in Walls Yourself
You need to conduct a proper assessment to determine the nature and extent of the cracks. If it needs professional support, call them. If it’s a minor crack, you can proceed with the following steps for minor wall crack repair:
- Surface Preparation: Begin by cleaning the cracked wall area, removing any loose debris, paint, or other contaminants. You can use a wire brush or scraper to do that.
- Routing of cracks: If the cracks are wider, consider creating a V-shaped groove with them using a crack-chasing saw or a masonry chisel.
- Application of the bonding agent: You need to apply a bonding agent or primer for the surface preparation, easing proper adhesion between the existing wall and the repair material.
- Choose Repair Material: Pick a suitable repair material, such as a weak or strong mortar mix, based on the type and severity of the crack.
- Finishing Work: After the application of the repair material, use a putty knife or trowel to smooth the surface.
- Painting and Restoration: Once the wall surface is fully cured, paint or finish it to match the surrounding wall surface.
Conclusion
Understanding cracks in the wall is essential in taking safety measures and preventing the building. Identifying the cause of damage in the building. Cracks are seen in both old and new buildings. They are not different, but we must take necessary and immediate actions. This helps prevent the spread of the cracks further. Cracks may pose a serious problem. While some cracks may pose a serious risk to the structural integrity of the entire building, others may be superficial and easily remedied. Determining the crack helps in choosing the appropriate method to fix the damage.
Frequently Asked Questions
Should I worry about cracks in walls?
A professional should always examine larger cracks wider than 5mm.
Can a cracked wall be repaired?
Yes, a cracked wall can be repaired. With a crack stitching kit, vertical and stepped cracks can be repaired to protect the structure of your home.
Is it safe to ignore wall cracks?
No, it is completely unsafe to ignore wall cracks as they can be a sign of serious underlying structural issues that threaten your home’s integrity.
How do I tell if a crack is structural?
You can tell a crack is structural if it’s wider than 1/10 inch, grows over time, or appears as stair-step, horizontal, large diagonal, or continuous ceiling-to-wall cracks.
Is concrete screed waterproof?
No, concrete screed is not naturally waterproof as it absorbs moisture. To make it waterproof, you need membranes, additives, or damp-proof layers, especially in wet areas like bathrooms.
Apoorva H P Achar