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Seeing foundation cracks may be alarming for homeowners. Are they normal, or are they a sign of something more serious? The answer depends on the type and severity of the crack.
In this article, we’ll discuss what causes foundation cracks, how to identify them, and what you can do to repair them.
So, let’s get started.
What Are Foundation Cracks?
Foundation cracks are fractures or splits in a home’s foundation that may pose a risk to its structural integrity. These cracks can develop for various reasons and may vary in size, shape, and severity.
Foundation cracks are typical in homes. In fact, it is safe to say that all homes have some foundation cracks. However, not all cracks in the foundation are created equal. Some are minor and can be repaired with a simple plaster, while others may require more extensive foundation repairs.
What Causes Foundation Cracks?
There are many reasons why a structure’s foundation may crack. Some of the most common causes include:
Poor Drainage
Water is one of the biggest causes of structural problems, especially in foundations. Water always flows to the lowest point, and the foundation is the lowest point of a home. Drainage problems such as a lack of gutters or downspouts, clogged drains, and poor grading can all cause water to pool around the foundation. Leaky pipes can also contribute to the water accumulation.
The pooling of water can result in the buildup of hydrostatic pressure. According to the University of Hawaii, hydrostatic pressure refers to the force exerted by the weight of water on objects that are submerged or in contact with it. Hydrostatic pressure does increase with depth. So, if the water problem is deep enough, the pressure is strong enough to cause damage to the foundation. The pressure exerted by accumulated water can lead to the formation of cracks in foundation walls.
In extreme cases, the consistent force from hydrostatic pressure can cause your foundation walls to lean or bow inward. This can compromise the entire structural stability of the building.
Climate
As temperatures rise and fall, most materials expand and contract, according to Penn State Engineering. This can create stress within the foundation, causing it to crack over time.
Additionally, natural disasters and seasonal changes can also cause foundation problems. Floods and heavy rainfall can cause water problems. Winter may cause frost heaves, where water expands when frozen, causing foundation cracks.
Poor Construction Practices
Inadequately constructed foundations can lead to numerous structural issues, including cracks and long-term durability problems. Foundations lacking proper steel reinforcement (rebar) are more susceptible to cracking under stress. Using inferior-quality concrete or not allowing it to cure correctly can also result in a weaker foundation prone to cracking.
Soil Conditions
The type of soil on which your foundation is built can also affect its stability. Expansive soils refer to soils that significantly change in volume with moisture content variation. Clay is a prime example of an expansive soil. These types of soils expand when they absorb water and contract when they dry out.
According to the State Government of Victoria, soil tests evaluate the soil’s reactivity, indicating how much it will shrink or swell in response to changes in moisture levels. Higher reactivity increases the likelihood of significant movement in the house’s footings.
Soil classifications include:
You can find a copy of the soil report within your approved building permit documents.
Additionally, when the soil beneath a foundation isn’t properly compacted before construction, it can settle unevenly once the structure is built, causing the foundation to crack.
Large Trees and Vegetation
Large trees and dense vegetation near a foundation can also lead to cracks. Tree roots can pressure the foundation as they grow and expand, causing cracks and other structural issues. Vegetation absorbs water from the soil, which can lead to soil shrinkage. These fluctuations can cause the foundation to settle unevenly and develop cracks.
Seismic Activity
Seismic activity, including earthquakes, can also cause foundation cracks. The ground shaking during an earthquake stresses the foundation, potentially leading to cracks or structural failure.
Types Of Foundation Cracks
You may notice that the cracks in your foundation are of different sizes and shapes. This is because there are several different foundation cracks, each with its cause and solution.
Here are some common foundation cracks:
- Vertical cracks are those that run straight up and down or slightly diagonal. These often occur due to the shrinkage of concrete, the settling of the foundation, or minor ground movements. Although usually less severe, they should still be monitored for any changes. However, if you notice that the crack is widening, getting longer, or the number of cracks is increasing, it may be a sign of more severe damage.
- Horizontal cracks run parallel to the ground and are typically caused by pressure from soil (hydrostatic pressure) pressing against the foundation walls or differential settlement. These more serious cracks can indicate significant structural issues or potential wall collapse.
- Diagonal cracks run at an angle and are often wider at one end. These are usually the result of uneven settling of the foundation. They are normal but can be serious if the cracks start to widen, requiring professional assessment.
- Stair-step cracks have a pattern that resembles a staircase and often appear in brick or concrete block foundations. These cracks usually occur due to differential settling of the foundation, especially at the corners or near load-bearing points. This is a sign of a serious foundation problem.
- Shrinkage cracks are thin, hairline cracks that appear shortly after pouring concrete. They are typically caused by rapid drying or improper curing of the concrete. These cracks are usually not a concern but should be monitored nonetheless.
How To Repair Serious Foundation Cracks
Serious foundation cracks require professional repair. Do not try to DIY your way out of it; your foundation is one of the most important parts of your home and should be treated as such.
Professionals may recommend the following repair methods:
- Pier Installation: Pier installation involves stabilizing and lifting sinking or settling foundations using steel piers (push or helical). The process includes driving steel piers deep into stable soil or bedrock beneath the foundation and using hydraulic jacks to lift up and stabilize the foundation. This method is ideal for addressing severe settling or sinking foundations.
- Carbon Fiber Straps: Carbon fiber straps reinforce and stabilize walls with minor to moderate cracks. The process involves applying a strong epoxy adhesive to the wall and securing carbon fiber straps over the cracks. This method is effective in preventing further cracking in foundation walls.
- Wall Anchors and Helical Tiebacks: Wall anchors and helical tiebacks are techniques used to stabilize and straighten bowing basement walls. For wall anchors, metal anchors are installed in the soil outside the foundation, and steel rods are connected through the wall and tightened gradually to pull the wall back into place. For helical tiebacks, the process involves inserting helical tiebacks into the ground and tightening them to pull the wall back.
- Grouting and Mudjacking: Grouting and mudjacking involve injecting material beneath the foundation to lift and level settled areas. Mudjacking involves drilling small holes into the foundation slab and pumping a slurry mixture of cement, sand, and water into the holes to lift the foundation back to its original position or as close as possible. Grouting involves injecting a grout mixture into drilled holes to fill voids and stabilize the foundation. These methods are used to address minor to moderate settling.
Contact The Foundation Pros
Have you noticed cracks in your home’s foundation? We offer free estimates on all of our services, including foundation repair, so you can get an idea before making any decisions. Contact us today for more information about our foundation repair services.
