When your foundation settles, structural piers transfer the load to stable soil or bedrock. Learn about helical and push pier systems and the installation process.
Helical vs. Push Pier Systems
Two types of deep foundation piers dominate residential repair. Helical piers resemble large screws—they have one or more helical plates welded to a steel shaft. The pier is rotated into the ground using hydraulic torque until it reaches bearing capacity. Helical piers are ideal for: lighter structures (decks, porches, additions), sites with variable soil conditions, and locations where installation vibration must be minimized. Push piers (also called resistance or pressed piers) are galvanized steel pipe sections driven into the ground using the weight of the foundation as resistance. A hydraulic jack pushes the pier sections downward until they reach refusal (solid bearing). Push piers are stronger than helical piers and are preferred for heavy structures, deep settling, and clay soils. Both systems are load-tested during installation to verify capacity. The engineer specifies which type based on soil conditions and structural loads.
The Pier Installation Process
Professional pier installation follows a systematic process. 1. Engineering assessment: a structural engineer reviews soil reports and foundation movement to design the pier system. 2. Excavation: small pits are dug at each pier location to expose the foundation footing (interior) or the foundation base (exterior). 3. Bracket installation: a steel bracket is bolted to the foundation footing (for push piers) or the foundation wall (for helical piers). 4. Pier driving: pier sections are driven or rotated into the ground, one at a time, until design capacity is reached. Torque or pressure is monitored continuously. 5. Lifting: if the foundation needs lifting, hydraulic jacks lift the foundation to the target elevation (limited to what the structure can withstand without cracking). 6. Load transfer: the pier is locked in place, transferring the foundation load to the bearing stratum. 7. Restoration: pits are backfilled, and disturbed areas are restored. The process takes 2–4 days for a typical home.
The Role of a Structural Engineer
Foundation piering should always begin with a structural engineer's assessment—not a contractor's sales pitch. The engineer will: review the soil conditions (from soil borings or existing geotechnical reports), measure the foundation elevation with a survey (floor level survey or laser level), assess the extent of settlement (differential vs. uniform), determine the cause of settling (soil compression, erosion, tree roots, etc.), and design the pier system (type, number, spacing, and depth). A qualified engineer charges $500–$1,500 for a residential foundation assessment and pier design. This investment prevents over-piering (paying for more piers than needed) or under-piering (the settling continues). Insist on an engineer's report—if a contractor does not require one, get a second opinion. The engineer's certification is also required for building permits in most jurisdictions.
Piering Cost Factors
Foundation pier costs vary widely by project. Per-pier cost: $1,000–$3,000 installed (includes bracket, pier sections, installation, and load testing). Number of piers: determined by the engineer. Access: interior installation (breaking basement floor) costs more than exterior installation. Depth: deeper piers cost more—typical pier depth is 15–40 feet depending on soil conditions. Lifting: if the foundation must be lifted (not just stabilized), costs increase due to the careful, staged lifting process. Restoration: patching holes in basement floors, restoring landscaping, and repainting are additional. Driveway or patio restoration adds significantly to cost if piering is needed under concrete. Total project cost: $5,000–$20,000 for a typical residential foundation repair. Most contractors offer financing. Some insurance policies cover foundation piering if caused by a covered peril (plumbing leak erosion).
Cost Overview
$1,000–$3,000 per pier
After Pier Installation
After piers are installed, the foundation movement stops. Monitor the repair: the contractor should provide a load test certificate and a warranty (typically 25 years to lifetime). Check the pier points annually for signs of new movement. Continue to maintain proper drainage around the foundation—saturated soil can still cause problems even with piers in place. Seal any cracks that remain in the foundation (some may open slightly during lifting). Fill and patch interior wall cracks that result from the settling. Repaint or retouch affected interior walls. The grade around the foundation may need adjustment after piering if the foundation elevation changed. Most settling is fully arrested by proper piering, giving you peace of mind that your foundation is stable for the long term.
Frequently Asked Questions
Helical piers have screw-like plates that are rotated into the ground—they work well in softer soils and can be installed with less weight. Push piers (also called resistance piers) are driven into the ground using the weight of the foundation itself—they work best in denser soils and provide more load capacity.
Symptoms include: doors and windows that stick, cracks in drywall and brick veneer, sloping floors, gaps between walls and ceilings, and visible foundation cracks wider than ¼ inch. A structural engineer's report confirms whether piering is needed.
Pier spacing is determined by a structural engineer based on soil bearing capacity and foundation load. Typical spacing is 6–10 feet apart along the affected foundation section. A single corner settling may need 2–4 piers; an entire side may need 8–12 piers.
Yes, both helical and push piers can be installed from inside the basement. The contractor breaks a small section of the basement floor (typically 2×2 feet) to access the footing. Installation from inside avoids disturbing landscaping and is common for finished homes.
Yes, properly designed and installed piers transfer the building load to stable soil or bedrock, stopping further settling. Piers are a permanent solution. The foundation may not return to its original level—the goal is to stop movement, not necessarily to lift the foundation.
Cost Overview
$1,000–$3,000 per pier
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