HOW HELICAL PILES WORK

A helical pile, also called a screw pile, is a steel shaft with one or more helical plates welded along its length.

A certified installer drives it into the ground using a hydraulic motor mounted on an excavator. As the pile rotates, the helices pull it downward through the soil at a controlled rate, threading it in like a screw into wood.

When the pile reaches bearing soil below the frost line, torque resistance confirms it has the load capacity needed for your project.

That is the short version. The longer version explains why this method outperforms concrete in speed, precision, and long-term stability.

What you are actually installing in the ground

The central shaft is solid round or hollow square steel, typically ranging from 2.875" to 4.5" in diameter depending on the application. The shaft transmits rotational force during installation and bears the vertical load once in place.

The helical plates are one to three steel plates welded to the shaft at a specific pitch, typically 3 inches. The pitch controls penetration rate. One full rotation advances the pile exactly 3 inches. This predictability is what allows installers to calculate depth with precision, not guesswork.

The bracket or cap is the steel connection at grade that transfers the structure's load to the pile. Brackets are custom-fabricated for wood beams, steel beams, concrete piers, and other structural connections.

All Postech piles are hot-dip galvanized according to ASTM-A123M standards or epoxy-coated depending on soil conditions and exposure. This is not optional corrosion protection. It is part of the engineering specification.

Step 1. Site Assessment & Layout

Before a single pile goes in the ground, a certified Postech installer reads your site. This means reviewing the project plans, identifying load points, and if needed, consulting soil data or a geotechnical report for challenging conditions.

Most residential projects (decks, additions, sheds) do not require a geotech report. Commercial and high-load applications may. Pile locations are marked, and the installer confirms frost depth requirements for your region.

Step 2. Excavator Setup & Calibration

Postech installers use hydraulic drive heads mounted on compact mini-excavators purpose-built for helical pile installation.

Their tight footprint allows work in spaces a standard excavator cannot access. Equipment is calibrated before each project to ensure accurate torque readings. Torque measurement is the primary method for confirming load capacity in the field.

Step 3. Driving the Pile

The pile is positioned at the marked location and advanced into the ground by rotating it with the hydraulic drive head.

The installer monitors three things simultaneously: plumb (vertical alignment), rotation count (depth by pitch calculation), and torque (load-bearing resistance). Rotation speed is typically 15 to 25 RPM. The helices cut through soil rather than displacing it, which minimizes ground disturbance.

On a standard residential deck with 6 to 10 piles, a two-person crew completes installation in 3 to 6 hours.

Step 4. Torque Verification

At final depth, the installer records installation torque using the calibrated drive head. This torque value is converted to an estimated load capacity using an empirically validated correlation factor specific to the pile geometry.

The torque reading is the quality-control checkpoint. If a pile does not reach minimum torque at the specified depth, the installer either drives deeper, changes the pile diameter, or adjusts the layout.

Step 5. Bracket Installation & Leveling

Once all piles are confirmed at bearing depth, brackets are installed and leveled.

For wood-frame decks and additions, this means adjusting the bracket height so your beam sits perfectly level regardless of grade changes across the site. This is one of the practical advantages over concrete: brackets are field-adjustable. Poured footings are not.

In Canada, seasonal frost heave is the leading cause of foundation movement in residential structures.

When soil moisture freezes, it expands. If your foundation anchors in the active frost zone, that expansion pushes the structure up. When it thaws, the structure settles back, unevenly. Over years, this produces cracked decks, unlevel floors, and structural damage.

Screw piles solve this by anchoring below the frost line, in soil that does not freeze.

The pile shaft passes through the active zone but does not transfer heave forces to the structure. Why? Because the helices are positioned in stable bearing soil below the frost line, the pile shaft is smooth through the frost zone, and a calculated clearance of 4 to 8 inches is maintained between the soil surface and the bottom of the structure.

This is not a workaround. It is the correct engineering approach for foundation design in freeze-thaw climates, and it is consistent with the National Building Code (NBC) of Canada and residential construction standards across all provinces.

What a helical pile can actually hold

Load capacity depends on three variables: pile diameter and geometry, soil type and density, and installation depth.

A standard residential deck pile (3.5 inch shaft, single helix, 5.5 feet deep, typical Quebec clay-sand soil) provides a working axial load capacity of 20 to 40 kips (44,000 to 88,000 lbs) per pile. A typical deck requires 6 to 10 piles. The math confirms the structure is carried with significant safety margins above code.

For commercial applications, multi-helix configurations on larger diameter shafts are used, with capacity reaching 100+ kips per pile. Full load capacity tables are in the Engineering documentation library.

For any commercial project, solar array, or structure requiring permitted engineered drawings, engage a licensed engineer. Postech provides technical documentation to support that process.

Postech does not sell screw piles to homeowners for self-installation. Every Postech pile is installed by a certified dealer who has completed the Postech training program.

Certification means the installer has been trained on equipment calibration, torque interpretation, pile selection, load calculation, and code compliance.

It means they carry the documentation needed to support a building permit application. And it means the lifetime warranty on your installation is backed by Postech, not just a contractor's verbal assurance.

When you hire a certified Postech installer, you are not paying for someone to operate a machine. You are paying for the engineering judgment behind the machine.