Common Causes of Sunken Concrete and How to Fix It
- ale0943
- Jul 31
- 4 min read
Common Causes of Sunken Concrete and How to Fix It
Sunken concrete is one of the most common property issues homeowners and property managers face in Illinois. Driveways, sidewalks, patios, garage floors, pool decks, and walkways settle over time, creating trip hazards, poor drainage, reduced curb appeal, and potential foundation problems. At SAVE Concrete, we specialize in raising and leveling sunken concrete using a calibrated cement-based slurry. This proven method restores slabs to their original position without the cost, mess, or waste of full replacement. Understanding the root causes of sunken concrete is the first step toward a lasting repair.
Poor Base Preparation and Installation
Many sinking problems start during construction.
Insufficient base or poor base composition leaves the slab without adequate support.
Base not properly compacted or bad bedding allows soil to settle under the concrete’s weight.
Low-cost installations or poor land improvement during construction often skip proper soil preparation and compaction.
Poor overall installation practices create weak foundations that fail years later.
Over decades of settling, even well-built slabs can experience gradual compaction of the underlying soil, especially in areas with fill dirt or disturbed ground.
Water Erosion, Drainage, and Landscaping Issues
Water is the leading cause of sunken concrete.
Downspouts that discharge water near the base of slabs wash soil away.
Improper grading, big slopes that let water rush, or low landscaping directs runoff under the concrete.
Poor drains, underground utilities drainage, or water flow problems create continuous erosion.
Water near the base, combined with no sealing of the concrete, allows moisture to penetrate and carry soil particles away.
Bad landscaping or landscaping issues that leave soil too low around slabs accelerate washout.
Drought followed by rainy seasons causes soil to shrink and then erode when water returns.
These conditions create voids beneath the slab. Once support is lost, the concrete sinks under its own weight or the weight of vehicles and foot traffic.
Weather-Related Expansion, Contraction, and Seasonal Changes
Illinois weather plays a major role.
Expansion and contraction due to temperature swings stress the soil and concrete.
Freeze-thaw cycles common in Northern Illinois winters cause soil to heave and then settle.
Dry and rainy seasons, plus drought conditions, make clay-heavy soils expand when wet and shrink when dry, forming voids.
Over time, repeated cycles leave the slab unsupported in places.
Animals, Critters, and Tree Roots
Biological activity undermines concrete more often than many realize.
Digging or tunneling of animals (critters such as moles, groundhogs, or rodents) removes soil from under slabs.
Tree roots grow and shift soil, creating uneven support or lifting sections that later settle.
These issues are especially common near landscaping, gardens, or mature trees.
Heavy Loads and Structural Stress
Heavy vehicles repeatedly driven over driveways or parking areas compress soil that was never fully stabilized.
Lack of control joints leads to uncontrolled cracking. Once cracks form, water enters more easily and accelerates settlement.
Combined with the factors above, these stresses turn minor settlement into noticeable sinking.
How to Fix Sunken Concrete the Right Way
The most effective, long-lasting solution for most sunken slabs is professional concrete raising with a high-quality cement-based slurry. At SAVE Concrete, our process works as follows:
We strategically drill small holes through the settled slab.
We inject a calibrated, premium Portland cement-based slurry under controlled pressure.
The slurry fills voids, displaces unstable material, and hydraulically raises the concrete back to its original level.
The material creates a strong, water-impervious subgrade that supports greater loads than native soil while remaining lower density than solid concrete.
This method is completed in hours rather than days. Most surfaces can be used the same day, and driveways are typically drivable within a few hours. It costs roughly one-half to one-third the price of full replacement, produces minimal mess, requires no re-landscaping, and keeps old concrete out of landfills. Our calibrated cementitious slurry provides a permanent repair when the underlying causes (especially water and drainage) are also addressed. We back our work with one of the strongest warranties in the industry.
After raising, we often recommend exterior caulking to prevent soil wash and a clear, penetrating concrete sealer that fills capillaries and creates a waterproof barrier. These steps protect the investment and extend the life of the repair.
Preventing Future Settlement
Address the root causes:
Extend downspouts and improve grading so water flows away from slabs.
Maintain proper landscaping heights and avoid low spots near concrete.
Seal concrete regularly and caulk joints.
Avoid parking heavy vehicles on areas with known soft soil when possible.
Monitor for animal activity and manage tree roots near slabs.
For new pours, insist on proper base compaction, adequate thickness, and correctly placed control joints.
Why SAVE Concrete Is the Choice for Illinois Property Owners
SAVE Concrete is the only contractor in Illinois using state-of-the-art technology with calibrated cementitious slurry for concrete raising, leveling, and void filling. We serve residential, commercial, industrial, and community association clients across the Chicago metropolitan area and Northern Illinois. We raise driveways, sidewalks, patios, stoops, pool decks, garage floors, and more—saving customers time, money, and the environmental impact of replacement. If your concrete is sunken, uneven, or creating drainage problems, do not wait for the issue to worsen.
Contact SAVE Concrete today for a free, no-obligation on-site evaluation.
Call 847-336-3400 or visit SaveConcrete.com.
Raise your concrete. Don’t replace it.
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