Foundation heave is a serious issue that requires prompt attention as soon as it is detected. The first step to resolve this problem is identifying the cause of heaving. This is essential for engineers to select the appropriate solutions to address the issue.
One of the major causes of foundation heave is soil saturation underneath the foundation. In such cases, the engineers must identify the source of water causing soil saturation and take steps to eliminate it to prevent further heaving.
After identifying the source of water, the engineers must specify and implement an appropriate repair or rehabilitation method based on the severity of the foundation damage. If the damage is minor, small repair work, such as concrete grinding of the outdoor slab, will be sufficient. However, if the damage is severe, extensive and costly repair work will be necessary. This may include ground injection to stabilize soil under the foundation and repair of the foundation structure.
Sources of Water
Foundation heave of a structure can be caused by various water sources. These include leakage of underground pipes, clogged drains, broken sprinkler lines, faulty gutter and leader systems, as well as pressure from tree roots and adjacent structures. These factors can contribute to excess moisture around the foundation of a building, leading to soil expansion and subsequent heave, which can cause significant damage to the structure over time. It is essential to identify and address these water sources promptly to prevent foundation heave and ensure the stability and longevity of the building. Regular maintenance and inspection of these water sources can help detect and rectify any issues early on, minimizing the risk of foundation heave and related structural damage.
How to Repair Foundation Heave?
1. Control Moisture
Moisture is the primary cause of foundation heave, and controlling water around a structure is the most effective way to address this problem. To prevent water pooling around the building, proper measures should be taken, such as installing rain gutters, implementing proper drainage, and ensuring appropriate grading around the perimeter of the structure.
Rain gutters can divert water away from the foundation and prevent it from accumulating around the building. Proper drainage systems can also prevent water from pooling around the foundation, reducing the risk of soil saturation and heaving.
Additionally, appropriate grading around the perimeter of the structure can help channel water away from the foundation and prevent it from seeping into the soil. This can reduce the likelihood of moisture buildup around the foundation and minimize the risk of heaving.
Taking these preventive measures can help avoid foundation heave and prevent costly repairs in the future.
2. Repair Methods
Foundation heave can be resolved by addressing adjacent water sources, such as repairing leaks in plumbing. However, this simple solution does not always work, and severe damage can occur, requiring costly repair work.
Polymer injection is a technique used to stabilize the soil underneath the foundation, which can resist water infiltration and mitigate the effects of foundation heave. For minor heave on outdoor concrete elements like slabs, grinding the concrete surface can be an effective repair method. However, the underlying cause of heaving still needs to be eliminated.
In cases of severe foundation heave, extensive repair work is necessary to prevent further damage. Several foundation repair methods are available, including pier systems, wall anchors, helical tieback anchors, plate anchors, and carbon fiber wall supports.
Pier systems such as helical piers, slab piers, and push piers can be used to repair foundation heave. These piers differ in their load-carrying capacity and placement, but all can support and even lift foundation slabs. Helical piers are often considered the best approach to secure buildings against foundation heave since they are locked together, preventing upward movement of structures due to heaving. In contrast, push piers are not locked together but rather fit into one another, making them vulnerable to becoming unlinked due to uplift pressure.
The placement of piers involves excavation work around the foundation to make way for helical pier installation, as shown in Figure-1. Jigs can be used to lift the foundation to its original place, as depicted in Figure-2. Figure-3 shows the process of lifting the foundation, while Figure-4 illustrates the placement of helical pier.
FAQs
What is foundation heave?
When it comes to building a structure, a foundation is a crucial element that supports the entire weight of the building. However, in some cases, the foundation may experience upward movement due to the soil beneath it being soaked with water. This phenomenon is known as foundation heave, which occurs when expansive soil expands and pushes the foundation upwards. This can be a significant issue for the stability of the building and may result in structural damage. Therefore, it is essential to understand the causes and signs of foundation heave and take necessary measures to prevent or mitigate its effects to ensure the safety and longevity of the structure.
What are the sources of water that lead to foundation heave?
Leakage of underground pipes can cause significant damage to a property and surrounding areas. It can lead to water seeping into the soil and potentially causing foundation problems, which can be very costly to repair. If left unchecked, it can also result in water damage to buildings and the formation of sinkholes. Therefore, it’s essential to regularly inspect and maintain underground pipes to prevent any leakage.
Clogged drains are a common problem that can occur due to a variety of reasons, such as the accumulation of debris, leaves, and other materials. This can lead to slow drainage or even blockages, causing water to overflow and potentially damage buildings or landscapes. Regular cleaning of the drains can help prevent these issues and keep the drainage system functioning properly.
Broken sprinkler lines can cause water wastage, leading to increased water bills and reduced water pressure. They can also result in the formation of puddles, which can be a safety hazard, particularly in areas with heavy foot traffic. Proper maintenance and timely repair of sprinkler lines can help avoid these issues.
Faulty gutter and leader systems can cause water to overflow and seep into the foundation, causing significant damage to the property. It can also lead to soil erosion, which can affect the landscape’s appearance and stability. Regular inspection and cleaning of gutters and leaders can help prevent these issues and ensure proper water drainage.
Trees’ roots and pressure from adjacent structures can cause heaving, which is the upward movement of the soil. This can result in cracks in the pavement, buildings, and other structures, causing safety hazards and costly repairs. It’s important to take measures to prevent heaving, such as regularly trimming tree roots and monitoring the surrounding soil conditions.
How to control moisture around a structure to avoid foundation heave?
Foundation heave is primarily caused by moisture, and therefore, managing water around the building is the most effective method for preventing it. This approach entails preventing water accumulation around the structure, which can be accomplished through the implementation of rain gutters, adequate drainage, and proper grading around the perimeter of the building. By taking these measures, water is directed away from the foundation, reducing the likelihood of foundation heave.
What are the repair methods for heave-damaged foundations?
There are several methods available for stabilizing the soil underneath a foundation. One of these methods is polymer injection, which involves injecting a polymer material into the soil to increase its strength and stability. Another method is the use of pier systems, which involves installing support pillars deep into the ground to provide additional support for the foundation.
When it comes to addressing issues with the concrete surface, grinding is a common technique used to smooth out any imperfections or rough spots. This can improve the appearance of the surface as well as enhance its durability.
For walls that are experiencing structural issues, wall anchors can be used to reinforce and stabilize them. Helical tieback anchors and plate anchors are two types of wall anchors that can be effective in addressing a variety of issues, including bowing or cracking.
Finally, carbon fiber wall supports can be used to provide additional reinforcement for walls. These supports are made of high-strength carbon fibers and are applied directly to the surface of the wall, helping to distribute forces and prevent further damage.