Engineered Deep Foundation Systems
Helical Pier Systems
Torque-Verified. Load-Rated. Permanent.
Helical piers are screw-in steel piles that achieve measurable bearing capacity through the torque correlation method; giving you and your engineer verifiable proof that each pier has reached competent, load-bearing soil. We design, install, and document every helical pier system to ICC-ES AC358 standards.
Torque-to-Capacity Calculator
See how installation torque translates to bearing capacity per ICC-ES AC358.
Ultimate Capacity
15,000 lbs
Kt (5) × T (3,000)
Allowable Capacity
7,500 lbs
FS = 2.0
Formula: ICC-ES AC358
Qult = Kt × T → 5 × 3,000 = 15,000 lbs
Qallow = Qult / FS → 15,000 / 2.0 = 7,500 lbs
This calculator demonstrates the torque correlation method. Actual pier design requires site-specific geotechnical data, load analysis, and engineering judgment. All our installations are designed by a licensed Professional Engineer.
Every pier installed with real-time torque verification
Why Helical Piers
The only foundation pier with real-time capacity verification
Helical piers are the most engineered and verifiable deep foundation system available for residential and light commercial repair. Every installation produces a documented torque-to-capacity correlation for each pier.
Measurable Installation Torque
Every helical pier is installed with real-time torque monitoring. Unlike push piers (which rely on structure weight as reaction force), helicals give you a verifiable, quantifiable capacity reading through the ICC-ES AC358 torque correlation method.
No Structure Weight Required
Helical piers screw into the soil independently; they don't need the building's weight to push against. This makes them ideal for light structures, new construction, and situations where the structure can't provide sufficient reaction force for push piers.
Minimal Vibration & Noise
Installation uses hydraulic torque motors, not impact hammers. This matters for occupied buildings, sensitive equipment, and structures where vibration could cause additional damage during repair.
Tension & Compression Capable
Helical piers resist both downward (compression) and uplift (tension) forces. This is critical for retaining walls, grade beams with uplift conditions, and expansive clay soils that can push foundations upward.
Technical Deep-Dive
Anatomy of a helical pier
Understanding what you're buying matters. Here's what each component does and why the specifications matter for your home.
Lead Section
The first shaft section with one or more helical plates (helices) welded at specific pitch angles. The lead section determines the pier's bearing area in the target soil stratum.
Specification
Typically 1.5" square shaft (SS5) or 2.875" round shaft (RS2875) for residential. Helix plates: 8"–14" diameter, 3/8"–1/2" thick.
Helix Plates
True helical plates with a consistent pitch (typically 3" per revolution). The individual plate method assumes each helix acts as an individual bearing plate in the soil. Plate spacing must be ≥3× diameter to avoid inter-helix interaction.
Specification
Circular plates welded perpendicular to shaft at 45°–90° to ground surface. Common configs: single 10", dual 8"/10", or triple 8"/10"/12".
Extension Shafts
Added in sections until the helix plates reach competent bearing soil. Each section couples to the previous with a bolted or interlocking connection. Total depth ranges from 8' to 50+' depending on soil.
Specification
5'–7' sections. Material: high-strength steel (ASTM A500 Grade B/C or A252). Yield strength: 50,000–70,000 psi typical.
Foundation Bracket
The connection between the pier shaft and the existing foundation. Bracket design determines load transfer efficiency and whether the pier can actively lift the structure or only stabilize it.
Specification
Two main types: New construction embedded brackets (cast in concrete) or retrofit underpinning brackets (bolted to existing foundation edge).
Soil-Specific Design
How Austin's geology changes the pier design
A helical pier in East Austin clay is a fundamentally different design than one in West Austin limestone. Here's how we adapt to each soil zone.
Black Clay (Blackland Prairie)
Kt = 4–6East of I-35; Manor, Pflugerville, East Austin, Del Valle
Plasticity Index: 35–55+
Challenge
Extreme shrink/swell behavior. Active zone extends 8–15' deep. Helical piers must penetrate below the active zone to reach stable moisture equilibrium.
Pier Design Response
Typically 15–25' depth. Smaller helix plates (8"–10") to reduce installation disturbance. Anti-friction coating on shaft through active zone to prevent soil drag.
Edwards Limestone
Kt = 8–10+West of I-35; Westlake, Bee Cave, Lakeway, Dripping Springs
Challenge
Thin soil over limestone bedrock. Helicals may hit refusal before developing adequate torque in soil alone. Rock sockets or alternative pier configurations may be required.
Pier Design Response
Shorter piers (8–15') to limestone bearing. May require pilot drilling through rock. Smaller or no helix plates when bearing directly on rock.
Alluvial Deposits
Kt = 5–7Along Colorado River; South Congress, Riverside, Bouldin Creek, East Riverside
Plasticity Index: 15–30
Challenge
Mixed sand, silt, and clay. Variable density with depth. Water table influence. Requires careful torque monitoring to verify consistent bearing.
Pier Design Response
Multi-helix configurations (2–3 plates) to distribute load across variable strata. Moderate depth (12–20'). Torque verification critical.
Expansive Fill / Imported Soil
Kt = 2–4 (in fill), higher in nativeNew developments; Mueller, East Riverside, Domain area, Whisper Valley
Plasticity Index: Variable (unknown)
Challenge
Poorly documented fill soils from development grading. Unknown composition, compaction, and depth. Can't assume any bearing capacity in fill material.
Pier Design Response
Must penetrate entirely through fill to reach native bearing soil. Extended depths (20–35+') common. Geotechnical investigation essential before design.
Head-to-Head
Helical piers vs. steel push piers
Both are permanent deep foundation solutions. The right choice depends on your structure, soil, and load requirements; not on which one a contractor happens to stock.
| Feature | Helical Piers | Steel Push Piers |
|---|---|---|
| Installation method | Screwed in with hydraulic torque motor | Hydraulically pressed using structure weight as reaction |
| Capacity verification | Real-time torque correlation (ICC-ES AC358) | Hydraulic pressure reading (less directly correlated) |
| Reaction force needed | None; self-advancing | Requires structure dead load (minimum ~2 lbs/sq ft) |
| Load direction | Compression AND tension | Compression only |
| Ideal for | Light structures, new construction, tension applications | Heavy structures, deep bearing, retrofit underpinning |
| Typical depth (Austin) | 8–30 ft (to stable bearing) | 15–50+ ft (to refusal) |
| Cost per pier (Austin avg.) | $400–$600 | $450–$650 |
| Installation speed | 15–30 min per pier | 20–45 min per pier |
We install both helical and push pier systems and recommend based on your engineer's assessment; not on which system has a higher margin. Learn more about steel push piers →
The Process
From assessment to warranty: how we install helical piers
Every installation follows a documented, engineer-designed process. Here's what to expect.
Geotechnical & Structural Assessment
A Professional Engineer reviews soil reports, structural loads, and settlement patterns to specify pier locations, depth, helix configuration, and minimum installation torque. This isn't optional; it's the design basis for your entire repair.
Excavation & Bracket Mounting
We excavate alongside the foundation at each pier location (typically 2'×3' pits). Underpinning brackets are mounted to the foundation edge with anchor bolts or epoxy anchors, creating the structural connection between pier and building.
Helical Pier Installation
Using a hydraulic torque motor mounted on a mini-excavator, we advance the lead section into the soil. Extension sections are added until the pier reaches the specified depth and minimum torque value. Torque readings are recorded every 1' of depth on a per-pier installation log.
Load Transfer & Lift
Hydraulic jacks on each bracket simultaneously transfer the building load from the soil to the pier system. If the engineer has specified active lift, the structure is raised in controlled increments (typically 1/8" per pass) while monitoring for cosmetic and structural response.
Documentation & Warranty
You receive a complete installation report: per-pier torque logs, depth records, before/after elevation surveys, and the engineer's letter of completion. Our warranty covers both stabilization and re-leveling for the life of the structure.
Engineering Reference
Typical helical pier capacities in Austin soil
These are representative ranges based on local soil conditions and standard shaft configurations. Actual capacity is determined by installation torque and site-specific geotechnical data.
| Shaft Type | Helix Config | Typical Torque | Allowable Capacity |
|---|---|---|---|
| 1.5" Square (SS5) Standard residential | 8"/10" dual | 2,000–5,000 ft-lbs | 5,000–12,500 lbs |
| 1.5" Square (SS5) Heavy residential | 8"/10"/12" triple | 3,000–6,500 ft-lbs | 7,500–16,250 lbs |
| 2.875" Round (RS2875) Light commercial | 10"/12" dual | 4,000–8,000 ft-lbs | 10,000–20,000 lbs |
| 2.875" Round (RS2875) Commercial/industrial | 10"/12"/14" triple | 5,000–10,000 ft-lbs | 12,500–25,000 lbs |
Allowable capacities assume Kt = 5 (typical Austin clay) with FS = 2.0. Actual Kt values range from 3–10+ depending on soil type, shaft configuration, and installation conditions. Always design per site-specific geotechnical data.
Helical Pier FAQ
Technical questions answered
Have a site-specific question? Call us at 737-302-6202 ; we can discuss your soil conditions and engineering requirements.
- How deep do helical piers go in Austin soil?
- Depth varies dramatically by location. East Austin's black clay typically requires 15–25' to get below the active zone. West Austin over limestone may only need 8–15' to hit rock. The target isn't a specific depth; it's a specific torque value that confirms adequate bearing capacity in stable soil.
- What's the torque correlation method and why does it matter?
- The torque correlation method (ICC-ES AC358) relates installation torque to pier bearing capacity through a correlation factor (Kt) that varies by shaft type and soil conditions. It's the only real-time verification that each pier has reached competent soil. A pier installed to 20' with 1,500 ft-lbs torque may be less capable than a pier at 12' with 5,000 ft-lbs. Torque tells you the truth; depth alone doesn't.
- When should I choose helical piers over steel push piers?
- Helical piers are preferred when: the structure is too light to provide push-pier reaction force (porches, stoops, lightweight additions); you need tension resistance (retaining walls, uplift conditions); you're doing new construction pre-piling; or soil conditions favor screwed installation over driven. Push piers are preferred for heavy structures with deep bearing requirements.
- How many helical piers does a typical Austin home need?
- For partial repair (one side settling), 4–8 piers is common. Full perimeter stabilization of a 1,500–2,500 sq ft home typically requires 12–20 piers spaced 5–7' apart. The exact number is determined by the engineer's load analysis and the settlement pattern; not by a rule of thumb.
- Can helical piers be used for new construction in Austin?
- Absolutely; and they're increasingly specified by Austin structural engineers for new homes on problematic soil. Helical piers installed before the foundation is poured allow the slab to bypass the active clay zone entirely. This proactive approach costs 5–15% of total construction but prevents the 10–15% value loss that foundation failure causes.
- What happens if the pier hits rock before reaching target torque?
- In West Austin, this is common. If the helix plates encounter limestone before developing target torque in soil, the engineer may specify: (1) bearing directly on rock with modified capacity calculation, (2) pilot drilling through rock to seat helices deeper, or (3) switching to a rock-socket pier design. This is a design decision the engineer makes based on the specific conditions encountered.
Every pier tells you exactly how strong it is.
Helical piers are the most transparent foundation repair system available. Real-time torque data on every pier, documented depth logs, and PE-stamped completion reports. Get a free assessment and find out if helicals are right for your home.
Free assessment · PE-designed systems · Transferable lifetime warranty