Moving slabs can lead to serious concrete joint issues, including spalling, cracking, and uneven surfaces. Addressing this movement early is essential to maintaining the integrity of your concrete structures, minimizing repair cost and saving on lift equipment repairs.
Understanding the costs associated with filling these voids is crucial for making informed decisions. Concrete replacement can cost anywhere from $50 to $150 per square foot, depending on the specifics of the project. This guide will explore the causes of voids, the cost considerations for different repair methods, and the benefits of hiring a professional over attempting a DIY approach.
Causes of Voids Under Concrete Slabs
Several factors contribute to the formation of voids under concrete slabs. The most common causes include slab curl at joints, inadequate soil compaction, soil settlement, erosion, or decay of organic matter.
Slab Curl
Almost all newly installed floors will experience curling at the joints. Especially at unreinforced intermediate saw cuts. The slab lifts and creates a void beneath which will cause deterioration of the job as lift traffic increases. This is a very regular/ normal occurrence and addressing this in the first 1 to 2 years often saves significant repair cost in the future.
Inadequate Soil Compaction, Soil Settlement, Erosion, or Decay of Organic Matter
Inadequate soil compaction can lead to joint deterioration. It is often in combination with failures in the panels of the floor. Soil settlement and erosion are natural processes that can contribute to void formation.
Over time, the soil beneath a slab can settle due to natural compaction or the decay of organic matter within the soil. Additionally, erosion from water movement can wash away soil particles, creating voids.
Organic matter, such as tree roots or decomposed plant material, can also decay and leave gaps under the concrete.If this is determined through geo technical exploration. Foam injection may be a temporary solution. The best long term cost solution would be the removal of panels and replacement of properly compacted subbase and then concrete is often .
Methods for Filling Voids
Polyurethane Foam Injection
Polyurethane foam injection is a more modern and efficient method for filling voids under concrete slabs. This process involves injecting a high-density polyurethane foam into the voids, which expands and hardens to lift and support the slab.
Poly stabilization begins with drilling small holes through the concrete slab. These holes are typically much smaller than those used in mud grouting, reducing the potential for damage to the slab. Once the holes are drilled, a specialized nozzle is inserted, and the polyurethane foam is injected into the voids. The foam expands rapidly, filling the voids and stabilizes the slab. After the slab is stabilized, the drill holes are patched with concrete.
Advantages Over Mud grouting
Polyjacking offers several advantages over traditional mudjacking:
- Cleaner Process: The polyurethane foam injection process is much cleaner than mud grouting, with minimal mess and cleanup required.
- Foam Is Not Prone to Erosion: Unlike the slurry used in mudjacking, the polyurethane foam is resistant to erosion. This makes poly stabilization a more durable solution for filling voids.
- Lighter Material: The polyurethane foam is significantly lighter than the slurry used in mudjacking, reducing the risk of further soil settlement issues.
- Smaller Drill Holes: Poly stabilization requires smaller drill holes, which means less damage to the concrete slab and smaller patches.
Cost Considerations
The cost to fill voids under a concrete slab can vary widely based on several factors, including the extent of the voids, the size of the slab, and the chosen method for filling the voids. Generally, poly stabilization tends to be more expensive upfront compared to grouting, but it offers greater durability and fewer long-term maintenance costs.
Factors Influencing Cost
- Extent of Voids: Larger or more extensive voids will require more material and labor, increasing the overall cost.
- Size of Slab: Larger slabs require more material to lift and support, leading to higher costs.
- Accessibility: Slabs that are difficult to access or have obstacles around them may require additional labor, increasing costs.
- Method Chosen: Poly Stabilization typically costs more than mudjacking due to the higher cost of materials and specialized equipment.
Benefits of Hiring a Professional Concrete Repair Company
Hiring a professional concrete repair company offers several advantages that can ensure the longevity and effectiveness of the void-filling process.
- Expertise in Assessing and Addressing the Issue: Professionals have the experience and training to accurately diagnose the extent and cause of the voids. They can provide a comprehensive solution that addresses the underlying problem rather than just treating the symptoms.
- Proper Equipment and Materials: Professional concrete repair companies have access to specialized equipment and high-quality materials that are essential for effective void filling. This ensures that the repair is durable and long-lasting.
- Warranty and Guarantee on the Work: Reputable concrete repair companies typically offer warranties or guarantees on their work. This provides peace of mind, knowing that if any issues arise after the repair, the company will address them at no additional cost.
Conclusion
Filling voids under concrete slabs is vital for ensuring structural stability and longevity. While methods like polyurethane foam injection can be costly, they offer long-term benefits and durability. Understanding the factors influencing costs and the advantages of professional services can help business owners and managers make informed decisions.
Opting for professional repairs ensures expertise, proper equipment, and warranties, ultimately providing peace of mind and protecting your investment in your property. Prioritizing effective void-filling solutions today can prevent more extensive and costly repairs in the future.
