Helical piers and steel push piers are both proven foundation underpinning systems that transfer structural load from failing shallow soils to stable deep strata — but they work through different mechanisms and excel in different situations. Helical piers are screwed into the ground like a large bolt and work well in a wide range of soil conditions including those with limited overhead clearance; steel push piers are hydraulically driven straight down and are best suited to sites where very heavy structural load can be used to verify bearing capacity. In Savannah’s coastal Georgia soils, both have important applications, and the right choice depends on your specific soil profile, foundation type, access conditions, and load requirements.
How Each System Works
Helical and steel push pier systems used for underpinning are evaluated for code compliance by the ICC Evaluation Service, the body that certifies deep foundation products against the International Building Code.
Helical Piers: The Screw Anchor Approach
A helical pier (also called a helical pile or screw pile) consists of a central steel shaft with one or more helical (spiral) plates welded to it at specific intervals. An electric or hydraulic torque motor rotates the shaft, threading the pier into the ground in the same way a wood screw enters lumber. The helical plates do not drill or displace soil — they cut through it, using the mechanics of a screw to generate downward penetration without requiring a downward push force.
Installation depth is guided by two factors: reaching a target soil stratum identified in soil boring data, and achieving a minimum installation torque that correlates to load-bearing capacity. Once the pier reaches the required torque at the required depth, a galvanized steel bracket is attached to the pier shaft and secured to the foundation footing. The home’s load is then transferred through the bracket and pier to the competent soil far below.
Learn more about our specific helical pier installation services in Savannah.
Steel Push Piers: The Hydraulic Drive Approach
Steel push piers (also called resistance piers or hydraulic piers) consist of steel pipe sections joined end-to-end and driven straight down by a hydraulic ram. Unlike helical piers, push piers are not rotated — they are pushed. The driving force is the weight of the structure being supported: the hydraulic ram braces against a bracket mounted to the foundation footing and uses the home’s own dead load as the counter-force to push the pier down.
This is both a strength and a limitation of the system. The advantage: when the pier reaches a depth where the driving resistance exceeds the home’s load, you have proof that the pier can bear the structure (the home itself tested it). The limitation: the system requires sufficient structural load to drive the pier past problematic soils — very light structures may not provide enough resistance, and the pier could theoretically stop short of truly competent bearing material in very soft soil sites.
See our steel push pier installation page for specific details on this system.
Detailed Comparison: Helical vs. Steel Push Piers
| Factor | Helical Piers | Steel Push Piers |
|---|---|---|
| Installation method | Rotated/screwed into ground (torque motor) | Hydraulically pushed straight down |
| Driving force | Torque from motor — independent of structure | Dead load of structure itself |
| Load capacity verification | Torque correlation to capacity | Load-tested against structure during installation |
| Minimum structural load required | None — works on light structures | Yes — structure must be heavy enough to drive pier |
| Soil type performance | Excellent in varied soils, sand, soft clay, organic layers | Best in moderately stiff soils; can struggle in very soft clay |
| New construction use | Yes — widely used for pre-construction support | Rarely — limited by need for structural load |
| Limited access installation | Excellent — can be installed with small equipment | Good but requires hydraulic ram setup space |
| Interior (crawl space) installation | Yes — routinely installed with low-profile equipment | Yes — with low-headroom hydraulic equipment |
| Immediate load transfer | Yes | Yes |
| Structural lift potential | Yes — often used for active lifting | Yes — hydraulic system allows coordinated lift |
| Tension/uplift capacity | Yes — helical plates resist uplift | No — push piers resist compression only |
| Typical cost per pier | Somewhat higher (equipment cost, torque motor) | Somewhat lower (simpler equipment) |
| Best for coastal Georgia soils | Excellent — handles variable soil layers well | Good in sites with sufficient structural load |
Savannah Soil Conditions and Pier Selection
Savannah’s layered coastal geology creates specific pier selection considerations that are distinct from what contractors in piedmont or mountain regions encounter.
The Deep Bearing Challenge
In much of coastal Georgia, the first truly stable bearing stratum sits 20–40 feet below grade. The upper soil layers — loose fill, organic deposits, silty clay — do not provide reliable long-term bearing for a foundation. Both pier systems must reach past these layers. In areas like Wilmington Island or Garden City where organic marsh soils may extend to 15–20 feet before transitioning to sandy marine deposits, this deep-drive requirement is standard.
When Helical Piers Win in Savannah
Helical piers have several specific advantages for coastal Georgia conditions:
- Very soft upper soils: In highly organic or saturated soils near tidal waterways, push piers can struggle to advance because there is insufficient resistance in the soft upper material for the pier sections to join reliably. Helical piers rotate through these layers smoothly.
- Light structures: Older Savannah homes — particularly in the Historic District or Victorian Quarter — may be lighter frame-construction structures that do not provide enough dead load to drive push piers to depth. Helical piers install independently of structural load.
- New construction and pre-construction: When installing piers before a structure is built (to prevent future settlement), helical piers are the only option since there is no existing load to drive push piers. See our pre-construction pier installation page.
- Uplift resistance: In hurricane-zone construction, the helical pier’s resistance to both compression AND tension makes it the preferred choice where wind uplift loads must be resisted through the foundation system.
- Seawall and coastal structure applications: Helical piers are frequently used to reinforce seawalls, bulkheads, and retaining walls in tidal environments — applications where push piers are not suitable. See our seawall repair and retaining wall repair services.
When Push Piers Win in Savannah
Steel push piers have their own advantages that make them the better choice in specific Savannah-area scenarios:
- Heavy structures on stiff soils: Larger homes, commercial buildings, or structures on relatively stiff clay soils provide ideal push pier conditions. The load-testing nature of push pier installation provides a high degree of confidence in bearing capacity.
- Cost sensitivity on larger jobs: When a home requires 15–25 piers and soil conditions are suitable, push piers can deliver equivalent performance at a lower total cost than helical piers.
- Slab foundations with uniform loading: Many Pooler and Garden City slab homes that have settled due to fill compaction are good push pier candidates — the slab provides distributed load and the settled fill layers are eventually displaced to reach bearing strata.
Other Pier Options for Specific Savannah Applications
Beyond helical and push piers, Solid Foundation Repair Of Savannah offers additional pier systems for specialized applications:
- Slab piers: Compact pier systems installed through cores drilled in a concrete slab, used when overhead access or structural constraints prevent conventional bracket-mounted underpinning. See our slab pier installation page.
- Injection piers (mini-piles): Smaller diameter piers grouted into place, used in limited-access situations or as supplemental support. See our injection pier page.
- Polyurethane foam for void filling: Not a pier system but frequently used alongside pier installation to fill voids that have developed under settled slabs. See our polyurethane foam injection page.
The Selection Process: How We Decide
At Solid Foundation Repair Of Savannah, pier system selection is not guesswork. Our process since 1989 has been built on thorough site evaluation:
- Structural assessment: We evaluate the foundation type, construction, and load distribution to understand what the piers must support.
- Soil review: Available soil boring data for the area is reviewed. In some cases, we recommend a soil boring on the specific site before finalizing the pier design.
- Access evaluation: We assess excavation requirements, interior crawl space conditions, and equipment access to determine which system can be practically installed.
- Load analysis: Structural dead loads are estimated to determine whether push pier driving resistance will be adequate.
- System recommendation: We present our recommendation with the reasoning — not just a quote. Savannah homeowners deserve to understand why a specific system is being proposed for their home.
Questions to Ask Any Foundation Contractor
If you are getting multiple bids for pier installation, these questions will help you evaluate contractor competence:
- What are the soil conditions at depth on my property, and how do you know?
- What is the target installation torque (for helical) or target driving resistance (for push piers)?
- How deep will the piers need to go to reach competent bearing material?
- What is the design load per pier, and how many piers does that require for my structure?
- What warranty do you provide, and is it transferable if I sell the home?
Get a Site-Specific Pier Recommendation
There is no universal answer to “helical or push piers?” — the right choice depends on your specific home, soils, and conditions. What we can tell you is that after more than 35 years of installing both systems across Savannah, Richmond Hill, Brunswick, and the coastal Georgia barrier islands, our family-owned team has the local soil knowledge and installation experience to make the right call for your situation.
Call (912) 642-3890 to schedule a free foundation inspection and pier system evaluation. We will assess your home’s specific needs and provide a detailed, written proposal for the system that best fits your conditions and budget.
You can also reach out online to schedule your consultation. We serve Savannah, Richmond Hill, Garden City, Pooler, Wilmington Island, Whitemarsh Island, and Brunswick, GA — and we know the soils under every one of these communities.
Quick Summary
Helical piers and steel push piers are both proven underpinning systems but work differently. Helical piers are rotated into the ground like a bolt using a torque motor, performing well in varied soils and tight-access sites; steel push piers are hydraulically driven down using the structure’s own weight, making them best for heavy structural loads. In Savannah’s coastal Georgia soils, the right choice depends on soil profile, foundation type, and site access.