Repairing foundation issues can range from simple fixes to complex procedures, depending on the severity of the problem. Here are some common methods used to repair foundations:

1. Patching and Sealing Cracks: Minor cracks in a foundation can often be addressed by cleaning the crack and then filling it with masonry repair epoxy or a similar sealant. This is only suitable for small, non-structural cracks.
2. Slabjacking or Mudjacking: This method involves pumping a mixture of cement, soil, and water or a polyurethane compound under a slab or beam foundation to lift it back into its original position. This process is useful for correcting minor settling.
3. Piering or Underpinning: This is one of the most common methods for repairing serious foundation settlement. Deep foundation piers are driven or screwed into the ground beneath the foundation until they reach a more stable soil layer or bedrock. The foundation is then lifted onto these piers, stabilizing it and correcting any settlement.

• Push Piers: These are typically made of steel and are driven into the soil using hydraulics.
• Helical Piers: These have a screw-like design and are screwed into the ground, making them ideal for both compression (downward) and tension (upward) forces.

1. Wall Anchors and Tiebacks: If a foundation wall is bowing or leaning, wall anchors or tiebacks can be used. These devices are driven into the ground outside the foundation and then connected to the wall with a steel rod and plate. By tightening the connection, the wall can be gradually pulled back into alignment.
2. Carbon Fiber Strips: In some cases, carbon fiber strips can be adhered to a foundation wall to prevent it from bowing further. These strips are strong and non-obtrusive but are typically used for walls that haven't bowed too severely.
3. Drainage Improvements: Improving drainage around the foundation can prevent future issues. This can involve grading the soil so it slopes away from the foundation, installing a French drain system, or adding gutters and downspouts to direct rainwater away from the foundation.
4. Waterproofing: If water infiltration is a problem, the foundation can be waterproofed. This can involve applying a waterproofing membrane, installing a sump pump, or using other waterproofing treatments.
5. Root Barriers: If tree roots are causing foundation problems, a root barrier can be installed to redirect the roots away from the foundation.

It's important to consult with a structural engineer or foundation repair specialist before attempting to fix a foundation issue. They can assess the severity of the problem and recommend the most appropriate and effective solution. Foundation repairs can be costly, but they are essential for ensuring the safety and longevity of a structure.