6 Reasons Your Concrete Is Sinking & How to Stop It

Why does concrete sink? — And what can you do about it?

You’re not alone if you’ve ever noticed sunken concrete on your property. Many homeowners encounter this issue, which can impact safety and aesthetics. This comprehensive guide will delve into the various causes of sunken concrete and provide valuable insights on prevention and solutions to safeguard your property investment.

6 Common Causes of Sunken Concrete

1. Soil Erosion: Soil erosion is one of the primary culprits behind sunken concrete. Over time, heavy rainfall and runoff can wash away the soil beneath your concrete surfaces. This erosion weakens the foundation, leading to uneven surfaces and cracks in your concrete.
2. Poor Compaction During Construction: The quality of construction plays a crucial role in preventing concrete settlement. Inadequate soil compaction during initial construction can create voids beneath the concrete, causing it to sink over time. Proper compaction is vital to avoid future settlement issues.
3. Water Infiltration and Drainage Issues: Water infiltration poses a significant threat to concrete. Prolonged exposure to moisture can weaken the concrete’s integrity, leading to settlement problems. Effective drainage systems are essential to maintain concrete stability and subbase integrity.
4. Tree Roots and Vegetation Growth: The growth of tree roots and vegetation near your concrete slabs can contribute to settlement. Tree roots can exert significant pressure on the concrete, causing it to sink or crack. Managing root pressure through root barriers and innovative landscaping practices can help prevent damage.
5. Soil Consolidation Over Time: Natural soil consolidation is a gradual process where soil settles and compacts. While this is a natural occurrence, it can result in concrete sinking if not appropriately managed. Monitoring soil consolidation and taking preventive measures are vital to maintaining concrete stability.
6. Critters: Small animals, such as moles or groundhogs, can create voids underneath concrete by digging tunnels. These voids remove support from the slab, leading to sinking and instability.

Void under sidewalk caused by soil settling.

How to Prevent Concrete From Sinking

To prevent sunken concrete, consider the following measures:

1. Proper Site Preparation and Compaction: Strong foundations are essential for long-term concrete stability. Ensure correct site preparation and compaction during construction to prevent future issues.
2. Adequate Drainage Systems: Install effective drainage solutions and direct water away from your concrete slabs to maintain their integrity. Regular grading and maintenance are crucial.
3. Managing Tree Roots and Vegetation: Implement root barriers and smart landscaping practices to protect your concrete from root-related damage while preserving your greenery.
4. Routine Inspections and Maintenance: Regular inspections help identify issues early and allow for prompt action. Implement a DIY inspection checklist to monitor your concrete’s condition proactively.
5. Fill in Gaps and Cracks: Sealing joints, cracks, and surface gaps helps prevent water infiltration – one of the main causes of slab erosion and settlement. Use polymeric sand or a flexible, weather-resistant caulking or sealant to keep moisture out and support subbase stability.
6. Proactive Techniques like Polyurethane Foam Injection: Explore proactive techniques like polyurethane foam injection for concrete void filling and stabilizing to provide long-lasting preventative measures to settlement issues.

Self-Assessment Guide for Concrete Slabs

This self-assessment guide helps homeowners identify potential concrete problems. If you find issues beyond minor cosmetic imperfections, consult with professionals (Slab-Jack Kings!) for a comprehensive evaluation and appropriate solutions. Here’s the simple self-assessment guide to help homeowners evaluate the condition of their concrete surfaces to determine when action is necessary:

1. Surface Inspection:
   • Examine the entire concrete surface for noticeable cracks or fissures, and note their size and location.
   • Check for areas where the concrete appears uneven, sunken, or raised. Walk carefully to detect any unevenness.
2. Water Drainage:
   • Observe how water drains on the concrete. Ensure that water flows away from the surface and doesn’t accumulate.
   • Inspect nearby drainage systems (e.g., gutters, downspouts) to confirm they’re not causing water pooling
3. Vegetation and Tree Roots:
   • Inspect the proximity of trees and vegetation to the concrete. Look for signs of root intrusion or pressure.
   • Note visible cracks or uplifts caused by tree roots.
4. Visual Discoloration:
   • Check the concrete’s color and surface texture for unusual discolorations or rough patches.
   • Note any areas that appear significantly different from the rest of the surface.
5. Safety Hazards:
   • Look for tripping hazards, especially on walking or driving surfaces.
   • Identify loose or dislodged concrete pieces that could pose safety risks.
6. Overall Stability:
   • Assess the stability and firmness of the concrete as you walk across it.
   • Pay attention to areas that feel hollow or give way, and listen for unusual sounds or vibrations.
7. Crack Width Measurement:
   • Measure the width of any cracks you find using a ruler or measuring tape. Record these measurements.
8. Photographic Documentation:
   • Take clear photographs of areas with concerns, cracks, or noticeable issues.
   • These photos can be useful for professional consultations.
9. Maintenance History:
   • Review the maintenance history of the concrete, including past repairs or modifications, for context.
10. Professional Consultation:
    • If you discover significant cracks, substantial sinking, or structural concerns during your assessment, consider seeking the opinion of concrete experts or professionals for a thorough evaluation and solutions.

How to Stop Concrete From Sinking – DIY

Protect your concrete before problems arise with simple, effective DIY strategies. Regular surface cleaning, sealing visible cracks, and improving drainage are all small actions that can make a big difference. These preventative measures help preserve the integrity of your slabs and reduce the risk of future settlement issues — no heavy equipment required. By staying proactive, you play a direct role in extending the life of your concrete surfaces.

When to Call The Pros

While DIY maintenance is valuable, it’s important to recognize when a problem is beyond your control. If you notice major sinking, large or growing cracks, pooling water, or shifting slabs, it’s time to bring in the experts. Professional concrete lifting specialists like Slab-Jack Kings use advanced equipment and polyurethane foam injection techniques to stabilize your concrete safely and permanently. Don’t wait until a small issue becomes a costly repair.

The Long-Term Value of Prevention

Preventative care isn’t just smart — it’s economical. Addressing minor issues early can save you thousands on full slab replacements or structural damage down the line. Investing in maintenance now means fewer repairs, fewer hazards, and longer-lasting concrete.

Sunken Concrete Is Preventable

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