Does your foundation have cracks? If so, you may be wondering if they’re serious. The answer is yes and no. Some cracks may be just a cosmetic issue, while others can be a sign of serious foundation problems.
So, read on to learn more about stair-step cracks and how to determine whether they should be a cause of concern.
What Are Stair Step Cracks?
According to Architectural Digest, stair step cracks usually form in concrete block foundations. It is named this way because the cracks resemble a staircase pattern ascending through the concrete blocks.
Step cracking is usually a sign of foundation failure. It often arises due to external pressures against the wall, causing it to bow inward. When the pressure on the wall exceeds its resistance, cracks start forming in a step-like pattern.
Are Stair Step Cracks Serious?
Generally, you may need to hire a foundation crack repair expert to determine whether the cracks are serious or not. If the cracks are only visible along the mortar joints or are less than 1/8-inch wide, they may be cosmetic cracks only and not be a cause for concern.
However, you should contact a professional as soon as possible when you see the following signs:
- The cracks exceed ¼ inch in width
- The wall is bulging or bowing
- The stair step pattern is uniform and repetitive
- The concrete blocks seem displaced or damaged
If you see any of these signs, it’s time to call a foundation professional. The sooner you do, the less likely your foundation will need extensive repairs.
What Causes Stair-Step Cracks?
So, what causes these foundation cracks to form?
Foundation Settlement And Shifting
When constructed, a building’s foundation is designed to stand on stable ground. However, soil conditions can change over time due to various factors, leading to settlement or shifting.
If the soil under the foundation was not adequately compacted before construction, it might compact over time under the weight of the building. This weight can cause the foundation to settle unevenly. Uneven settlement can create stress on brick or block walls, manifesting as stair-step cracks. These cracks indicate that parts of the foundation have moved relative to each other.
Foundation Heaving
Foundation heaving is the upward movement of the foundation caused by soil expansion, usually due to increased moisture content. Clay soils tend to absorb large amounts of water, swelling significantly in the process. When the water content decreases, they shrink back, which can cause heaving and settling cycles, a property known as shrink-swell behavior or capacity.
Additionally, water in the soil can freeze and expand. This frozen water pushes the soil upward, affecting the foundation. This upward movement can crack the foundation and walls, with stair-step cracks being a common symptom.
Hydrostatic Pressure
Hydrostatic pressure is the force exerted by standing water in the soil around a foundation. High levels of groundwater or poor drainage can increase this pressure. As the pressure builds, it can push against foundation walls, leading to bulging, cracking, and ultimately stair step cracks. Left untreated, this can compromise the structural integrity of the building.
Poor Drainage
Improper drainage systems can result in water pooling around the foundation. When water is not effectively channeled away from a building, it can accumulate in the soil surrounding the foundation.
The combined effects of soil erosion, expansion, and increased hydrostatic pressure due to poor drainage can result in significant movement of the foundation. This movement manifests in the form of stair-step cracks.
Poor Construction
The longevity and durability of a foundation are highly dependent on the quality of its construction. Poor construction practices can make a foundation more susceptible to cracking and movement.
Foundations require proper reinforcement with rebar or steel mesh to handle stresses. Inadequate reinforcement can lead to cracks. If the concrete mix is too weak (e.g., wrong proportions of cement, sand, and aggregate), it can lead to a weak foundation. Concrete also needs to be adequately cured to gain strength.
Over time, a poorly constructed foundation may develop cracks due to everyday stresses and loads. Stair step cracks can appear as parts of the foundation shift or settle, compromising the stability of the structure.
Why Do You Need To Address Stair Step Cracks Immediately?
Structural Integrity
Stair step cracks often indicate underlying structural issues, such as foundation settlement or wall movement.
If you ignore these cracks, it can lead to:
- Increased Damage: Over time, small cracks can grow larger and compromise the overall stability of your structure.
- Safety Hazards: Severe structural failures could potentially result in portions of the wall collapsing, posing a significant risk to you as an occupant.
Water Infiltration
These stair step cracks create pathways for water to enter your home or building, leading to:
- Moisture Problems: Water infiltration can cause mold and mildew to thrive, which can affect indoor air quality and cause health issues.
- Material Degradation: Continuous water exposure can lead to the deterioration of building materials, like wood rotting or metal rusting, which can be costly to repair.
How Can You Tell If A Foundation Crack Is Structural?
Non-Structural Cracks
Non-structural or normal cracks typically result from natural settling, shrinkage, or minor shifts in the foundation. These cracks usually pose no immediate threat to the structural integrity of the building.
Here are some characteristics of non-structural cracks:
- Hairline Cracks: These are thin cracks less than 1/8 inch wide that usually occur during concrete’s natural curing process.
- Vertical Cracks: Cracks that run vertically or at a slight angle and are generally narrow commonly signify the normal settling of the house.
- Shrinkage Cracks: Typically found in poured concrete walls, these narrow vertical cracks are caused by the concrete shrinking as it cures.
- Plaster Cracks: These are fine cracks that appear on plastered surfaces, often resulting from the drying or curing process of the plaster. They do not affect the structural integrity of the wall but may need to be repaired for aesthetic purposes.
Structural Cracks
Structural cracks are more serious as they can threaten the integrity of the building.
Here are some characteristics of structural cracks:
- Horizontal Cracks: These cracks run horizontally along the foundation wall, often indicating pressure build-up from the soil outside the foundation. Such cracks can compromise stability and demand immediate attention.
- Stair-Step Cracks: Commonly found in brick or concrete block walls, these follow the mortar joints in a staircase pattern and can indicate foundation movement.
- Wide Cracks: Cracks wider than 1/8 inch (or 3mm), especially if they show signs of displacement (one side is higher or lower than the other), are often a sign of severe foundation movement.
- Cracks with Bulging: Any cracks accompanied by a bulging or bowing foundation wall point to severe structural issues, usually caused by soil pressure or water infiltration.
- Displaced Cracks: Cracks where one side is higher than the other, indicating differential movement in the foundation. This type of crack often signals a serious issue needing immediate professional assessment.
If You See A Stair Step Crack, Contact A Pro
If you see stair-step cracks in your foundation, it’s important to contact a professional right away. Stair-step cracks are usually signs of serious structural issues that must be addressed.
If you catch the problem early, it will cost less to repair.
At AMC911, we proudly serve Virginia Beach, Chesapeake, Norfolk, and the nearby areas with top-tier foundation repair services. If you ever encounter an issue with your foundation, such as a stair-step crack, reach out to us to learn how we can help resolve it.
