Piering vs. Slabjacking: Which Foundation Repair Method Is Right for You?
When you notice a sloping floor, a gap above your window frame, or a jagged crack in your basement wall, the first instinct is often a mix of stress and confusion. Your home is your most valuable asset, and "foundation trouble" is a phrase no homeowner wants to hear.
However, modern engineering has made foundation repair more precise and accessible than ever. The two most common professional solutions—piering and slabjacking—are often discussed together, but they solve very different problems. Choosing the wrong one could mean wasting thousands of dollars on a temporary fix, while choosing the right one can permanently secure your home’s value.
In this guide, we will break down the mechanics, costs, and long-term results of piering versus slabjacking to help you decide which path is right for your property.
Understanding the Basics: Piering and Slabjacking
While both methods aim to level a home, they operate on different principles of physics and soil mechanics.
What is Piering?
Piering (also known as underpinning) is a structural repair that involves driving heavy-duty steel or concrete cylinders deep into the earth. These piers are pushed past the "active" or unstable layers of topsoil until they hit solid bedrock or load-bearing strata.
Once the piers reach stable ground, hydraulic jacks are used to lift the house back to its original position. The weight of your home is then transferred from the failing soil onto these deep-seated stilts.
What is Slabjacking?
Slabjacking (often called mudjacking or poly-leveling) is a method used to lift sunken concrete slabs by injecting a material beneath them. Technicians drill small, penny-sized holes through the concrete and pump in either a cement-based "slurry" or a high-density polyurethane foam.
As the material expands, it fills the voids (empty spaces) created by eroded or settled soil, exerting upward pressure to float the slab back to level.
Comparing the Two: A Side-by-Side Breakdown
| Feature | Piering (Underpinning) | Slabjacking (Mudjacking/Poly-Leveling) |
| Primary Goal | Permanent structural stabilization. | Leveling surface concrete and filling voids. |
| Depth of Repair | Reaches bedrock or stable deep soil. | Affects only the area immediately under the slab. |
| Best For | Foundation walls, multi-story homes, sinking perimeters. | Driveways, patios, garage floors, interior slabs. |
| Invasiveness | High (requires excavation around the home). | Low (requires only small drill holes). |
| Longevity | Lifetime / Permanent. | 5–10 years (Slurry) to 10+ years (Foam). |
| Average Cost | $1,000–$3,000 per pier ($10k–$30k total). | $550–$1,500 per project. |
When to Choose Piering
If your home is experiencing structural settlement, piering is usually the only viable long-term solution. Structural settlement occurs when the weight of the entire building causes the foundation footings to sink into soft or expansive clay.
You should choose piering if:
You see "stair-step" cracks in exterior brickwork.
Your chimney is pulling away from the house.
Doors and windows are so misaligned they no longer lock or open.
The perimeter of your home is sinking, not just an interior floor.
You want a permanent solution that adds to the home's resale value with a transferable warranty.
When to Choose Slabjacking
Slabjacking is an excellent, cost-effective choice for non-structural leveling. It is ideal for concrete that has "settled" because the soil beneath it washed away or was poorly compacted, but the actual weight-bearing walls of the house remain stable.
You should choose slabjacking if:
Your driveway or sidewalk has become a tripping hazard.
Your garage floor or basement slab has a "hollow" sound when tapped.
You have a sunken patio or pool deck.
The issue is localized to a flat concrete surface rather than a load-bearing wall.
You are on a tight budget and need a quick fix for a localized interior floor slope.
Critical Factors: Soil Type and Drainage
The "right" choice often depends on the ground beneath your feet.
Expansive Clay: In regions with heavy clay, soil expands when wet and shrinks when dry. This constant "heaving" can eventually crack slabjacking material. Piering is preferred here because it bypasses this unstable zone entirely.
Sandy Soil: Sand doesn't shrink or swell, but it does wash away (erosion). If you have a void under a slab due to a leaky pipe or poor gutter drainage, slabjacking can fill that void and solve the problem permanently—provided you fix the water issue.
The Importance of a Structural Engineer
Before committing to a contractor, it is highly recommended to hire an independent structural engineer. Unlike a repair company, an engineer has no financial interest in selling you a specific service. They can perform a "manometer survey" to map exactly where your home is unlevel and tell you whether you need the heavy-duty support of piers or the simple lift of slabjacking.
Conclusion: Making the Final Decision
The choice between piering and slabjacking comes down to permanence vs. price.
Slabjacking is a fantastic tool for fixing cosmetic and safety issues on flat concrete surfaces. It is fast, affordable, and requires almost no cleanup. However, it relies on the surface soil to stay put. If the ground continues to sink, your slab will sink again.
Piering is a major construction project, but it addresses the root cause of the problem. By anchoring your home to the earth’s crust, you eliminate the risk of future movement. For most homeowners dealing with foundation wall cracks or major sinking, piering is the investment that provides true peace of mind.
Essential Guide to Foundation Repair: Protecting Your Home’s Value and Structural Integrity