3 Reasons Your Concrete Is Sinking: What to Do About It

Causes of Concrete Soil in Concrete Sinking

1. Soil Shrinkage

Soil shrinkage is a key factor in concrete settling. Here’s a concise breakdown:

• Soil shrinkage happens when moisture content decreases, causing soil volume to shrink.
• Weather conditions, especially drought, and tree roots significantly affect soil shrinkage. During drought, soil loses moisture and shrinks, creating voids beneath the concrete, leading to settling. Growing tree roots absorb soil moisture, creating voids and leading to shrinkage and concrete settling.
• Areas with expansive soils like clay or sandy soils, common in Florida and hot, dry climates, are especially prone to soil shrinkage.

To prevent concrete settling due to soil shrinkage:

• Maintain consistent soil moisture through proper landscaping and drainage practices.
• Regularly monitor soil conditions.

2. Poor Soil Compaction

When the soil beneath a concrete slab is not compacted properly, it can lead to concrete settling. Poorly compacted soil lacks the density and stability to support weight, which makes it a poor support for heavy materials such as concrete. When the soil underneath concrete is loose or shifts, it can compromise the support, leading to the concrete sinking or cracking.

This can happen for a variety of reasons such as:

• Improper preparation during the construction process or the inherent nature of the soil type. For instance, sandy soils, which are common in certain regions, do not compact well naturally.
• Weather conditions and other environmental factors like heavy rainfall can wash away loosely compacted soil, causing the ground to shift and destabilize.

It’s important to note that poor soil compaction is not always visible on the surface. It often occurs beneath the ground level, which means it can go unnoticed until significant sinking or damage has occurred. Therefore, it’s crucial to ensure proper soil compaction during the construction process and to monitor for signs of concrete settling regularly.

3. Soil Washout

Soil washout, often triggered by heavy rainfall, is a major contributor to concrete settling. This phenomenon, particularly prevalent on sloped terrains, entails rapid displacement of topsoil by water flow.

Certain types of soil, like sandy and fine-grained ones, are especially vulnerable to washout due to their poor water retention and loose consistency. Human activities, such as poor yard drainage and chemical pollution, can also exacerbate soil washout.

Plants and tree roots, by retaining soil and reducing rain impact, can help alleviate washout. However, a lack of foliage can increase the risk.

Remember, soil washout impacts more than just your yard—it undermines your concrete structures’ stability. As the soil washes out, your concrete can settle unevenly, causing damage like cracks. Addressing this issue is essential not only for your property’s aesthetics but also for the structural integrity of your concrete structures.

The Consequences of Concrete Settlement

Ignoring sinking concrete can lead to:

• Aesthetic issues: Cracks and uneven surfaces on driveways, sidewalks, or patios diminish your property’s appeal.
• Safety hazards: Uneven surfaces pose a tripping risk, especially in high foot-traffic areas like walkways and patios.
• Structural problems: Sinking concrete puts pressure on your home’s foundation, leading to cracks and potentially compromising your home’s structural integrity.
• Drainage issues: Uneven concrete can cause pooling water and improper drainage, leading to soil erosion, water damage, and mold growth.

Addressing signs of concrete settlement early, through regular inspections and prompt repairs, is vital to maintain your property’s safety, aesthetics, and value.

How to Stop Your Concrete Sinking: Lifting & Leveling

One effective solution for sinking concrete is a process known as concrete lifting or leveling. This process addresses the root cause of the problem, which is often the unstable soil beneath the concrete. By stabilizing the soil and lifting the concrete back to its original position, you can restore the aesthetics and safety of your property.

One popular method for concrete lifting is PolyRenewal™. This innovative process involves injecting a high-density polyurethane foam into the ground beneath the sunken concrete. This foam expands and hardens, filling any voids in the soil and providing a stable base for the concrete. Once the foam is in place, it lifts the concrete back to its original level.

The process of PolyRenewal™ is quick and efficient. Small holes are drilled into the sunken concrete slab, through which the foam is injected. The foam expands and hardens in place, lifting the concrete in the process. The entire process can be completed in a matter of hours, with the foam curing in just about 15 minutes. This means you can use your concrete surface almost immediately after the procedure.

The advantages of PolyRenewal™ are numerous. Unlike traditional mudjacking methods, which can be messy and time-consuming, PolyRenewal™ is clean and quick. The foam used in the process is also waterproof and resistant to heat, making it a long-lasting solution. Most importantly, it eliminates the need for extensive excavation or replacement of the concrete, saving you time and money.

If you’re dealing with sinking concrete, consider concrete lifting as a viable solution. With the help of a professional, you can restore the safety and aesthetics of your property in no time.

Call Alpha Foundations for Concrete leveling Today!

Sinking concrete, caused by factors like soil shrinkage, poor soil compaction, and washout, is a widespread issue. It’s often due to changes in soil moisture, improper construction, and environmental shifts. Ignoring it can lead to severe problems, from aesthetic damage to serious safety and structural risks.

Solutions such as concrete lifting and PolyRenewal™ effectively tackle this, stabilizing the soil and restoring the concrete, thus enhancing property aesthetics and safety. If you spot signs of concrete settling, obtain immediate professional inspection and repair.

Concrete Sinking FAQs

How fast does concrete sink?

Sinking concrete can happen as soon as a month after it is poured if the area of installation was not properly prepared and the underlying soil was incorrectly tamped. 

However, it is more realistic to see some settlement 10 years after the concrete slabs were poured. 

What causes concrete driveways to sink?

Concrete driveways sink due to erosion beneath the slabs caused by expansive soil, soil instability, water intrusion, and freeze/thaw cycles. Heavy vehicles parked in the same place for extended periods can also result in driveway sinking. Contact Alpha Foundations for a free inspection to determine the source of the problem and the best repair solution.

How can you tell if concrete is sinking?

Sinking concrete is generally easy to spot. You will start to notice the following: 

• Slabs that are uneven and don’t match up 
• Puddles form and remain after rain 
• People trip over the uneven surface 
• It’s more difficult to drive over your driveway or garage floor 

Ted Dryce

Content Writer

Ted is an SEO Content Writer who has been with Groundworks since 2021. He’s covered home repair topics ranging from crawl space encapsulation to regional soil conditions. When he’s not working, Ted is performing improv comedy and working on his own creative projects.

Related Resources

Tree Roots Breaking Concrete? Here’s What to Do

7 Reasons to Repair Your Concrete Steps

Concrete Leveling: A Homeowner’s Guide

_{*Disclaimer: “Concrete leveling” means the process by which cracked, uneven concrete is stabilized, and in many cases lifted, by means of PolyRenewal™ polyurethane foam. Alpha Foundations does not guarantee that PolyRenewal™ can make your concrete perfectly level.}