What Are Slab Piers?
Slab piers are a specialty foundation underpinning solution for homes built on slab-on-grade construction that have experienced significant foundation settlement. Unlike polyurethane foam slab lifting, which raises a slab by filling voids beneath it, slab piers are installed through the footing and driven to bedrock or load-bearing strata, permanently transferring the structural load away from the problem soil. APS Foundation uses slab piers when soil failure or severe settlement makes foam lifting insufficient for a lasting repair, a determination made during the free on-site assessment.
How Slab Piers Work
Slab foundations settle when the soil beneath the perimeter footing or interior load-bearing areas loses the density or volume needed to support the structure's weight. In cases of mild settlement with voids present, polyurethane foam lifting can restore grade and re-establish subgrade support. But when the soil itself has failed to the point that foam fill would not provide durable long-term support, slab piers are the correct structural solution. Slab pier installation begins with targeted access cuts through the interior slab at the pier locations. These cuts expose the footing below the slab surface. A steel bracket is then mounted to the footing, and the pier sections are hydraulically driven through the bracket, section by section, until the pier reaches load-bearing strata at the required depth. Once all piers on the project have been driven to their target depth and bearing verified, the lift sequence begins. Hydraulic jacks are synchronized across every bracket and the structure is lifted uniformly and carefully back toward its original elevation. The controlled, uniform lift is essential on slab foundations to avoid creating differential stress that could cause slab cracking. After the lift is complete and the piers are locked at the raised position, the access cuts through the slab are patched and finished. The result is a permanently stabilized foundation whose load has been transferred from failing near-surface soil to competent deep bearing strata. For Huntsville properties on karst geology where bedrock is at inconsistent depths, the inspector will evaluate whether helical slab piers are a more appropriate option, as torque-monitored installation provides real-time confirmation of load capacity regardless of bedrock consistency.
“When the soil has simply given up, foam filling gives you a temporary fix at best. Slab piers go past the problem soil entirely. We are putting the load on something that has been stable for thousands of years.”
How APS Installs Slab Piers
- 1
Free On-Site Assessment
An APS inspector evaluates the slab settlement, reviews the soil conditions for your area, and determines whether slab piers or polyurethane foam lifting is the right long-term solution.
- 2
Interior Access Cuts
Targeted cuts are made through the interior slab at each pier location to expose the footing below. These cuts are kept as small as possible and patched after installation.
- 3
Footing Bracket Installation
A galvanized steel bracket is mounted to the exposed footing at each pier location, serving as the pier guide and load transfer point.
- 4
Hydraulic Pier Driving
Steel pier sections are driven hydraulically through the bracket, section by section, until reaching load-bearing strata. Driving force and depth are recorded at each pier.
- 5
Synchronized Lift
Hydraulic jacks are synchronized across all pier brackets for a controlled, uniform lift. The slab is raised gradually; rate and uniformity are monitored carefully to avoid stress fractures.
- 6
Lock-Off and Slab Patch
Piers are locked at the lift position, access cuts are patched and finished to match the surrounding slab, and a complete warranty package is provided.
What Slab Piers Cost and What Is Covered
Cost Range
$2,000 to $4,500 per pier; most slab pier projects require 4 to 10 piers.
Warranty
Manufacturer warranty plus APS in-house warranty, transferable to new owners at no additional cost.
Frequently Asked Questions
How is slab pier installation different from standard push piers?
Standard push piers are typically installed through brackets mounted to the exterior perimeter footing with excavation from the outside. Slab piers are accessed from the interior through cuts in the slab, making them the appropriate solution for slab-on-grade homes where the footing is below the slab surface and exterior excavation is not practical or sufficient.
Why not just use polyurethane foam lifting instead?
Foam lifting is the preferred first option when the slab has settled due to void formation and the surrounding soil retains adequate bearing capacity. When the soil itself has failed, foam fill would eventually settle along with the weak soil. Slab piers bypass the problem soil entirely by transferring the load to stable bearing strata below, providing a permanent solution independent of near-surface soil conditions.
Will the access cuts through my slab be noticeable?
The patched cuts are visible on bare concrete as color variations where the patch material meets the original slab. If you plan to apply flooring over the slab, the patches will be hidden entirely. Our crew uses a patching compound sized and finished to minimize the visible difference.
Is my home in Huntsville a candidate for slab piers?
Huntsville's karst geology creates unique considerations for any pier-based solution. A site assessment is required before recommending driven slab piers in the Huntsville area. In some cases, torque-monitored helical slab piers are more appropriate because they confirm load capacity in real time without depending on consistent bedrock depth.