How Each Method Works
Helical Piers
A helical pier is a steel shaft with helical (screw-shaped) plates welded at specific intervals. It’s installed by rotating it into the ground using a hydraulic torque head - the same mechanical principle as a wood screw, at much greater scale and depth.
As the pier is screwed in, installation torque is monitored. When torque reaches the bearing capacity threshold, the pier has reached stable soil. The pier is then cut to grade, a bracket is attached to the foundation footing, and the structure is lifted.
No structural load is required during installation. This is the defining advantage: helical piers can be installed under porches, additions, decks, interior slab sections, and any other location where the structure’s weight isn’t sufficient to drive a pier.
Push Piers
A push pier (also called a resistance pier or hydraulic pier) is a steel pipe installed in sections. A hydraulic ram drives each section into the ground using the structure’s weight as a reaction force - the pier pushes against the house to go down.
When driving resistance exceeds the required threshold (verified by hydraulic pressure), the pier has reached bearing. After all piers are set, hydraulic jacks are used to lift the structure, and load is transferred to the piers.
The structure’s weight is required during installation. This limits push piers to locations where the load is substantial enough to drive the pier - typically the main perimeter of a full-weight residential or commercial structure.
Side-by-Side Comparison
| Factor | Helical Piers | Push Piers |
|---|---|---|
| Installation method | Rotated in (like a screw) | Hydraulically driven |
| Structural load required | No | Yes |
| Porches / additions / light structures | Yes | Usually not |
| Interior slab applications | Yes | Limited |
| Tight or low-clearance access | Often feasible | More difficult |
| Verification of bearing depth | Torque monitoring | Hydraulic pressure |
| Per-pier cost (equivalent depth) | $1,500-$3,500 | $1,200-$3,000 |
| Installation speed on heavy perimeter | Moderate | Generally faster |
| Typical warranty | 25 years-lifetime | 25 years-lifetime |
| Disturbance to yard | Access pits required | Access pits required |
When Helical Piers Are the Better Choice
Settling porch, deck, or addition: These structures typically lack the mass for push pier installation. Helical piers install cleanly without needing structural weight.
Interior slab settling: Beneath the slab, structural loads are often insufficient at interior points for push pier installation. Helical piers are drilled through the slab and screwed to depth.
New construction or pre-construction: Helical piers are commonly used to pre-install foundation support for structures in problematic soil zones before construction begins - push piers can’t be used before the structure is in place.
Tight access: Helical pier installation equipment is compact and can often access restricted areas (narrow side yards, under decks, within crawlspaces) where push pier hydraulic equipment cannot.
Soft soils at the surface: Push piers require skin friction along the shaft to drive - in very soft surface soils, a push pier may not be stable enough to set up. Helical piers screw through soft layers without relying on surface friction.
When Push Piers Are the Better Choice
Main perimeter underpinning of a full-weight home: Push piers are well-suited to perimeter pier installation on standard residential structures. Installation is often faster than helical, and the system is proven for this application.
Cost sensitivity on large projects: On an equivalent-depth basis, push piers are typically slightly less expensive. On a large project (12+ piers) the cost difference can be meaningful.
Rocky or dense soils at depth: In some soil conditions, push pier driving performs better than helical screw-in. Local contractors who know your area’s soil profile can advise.
What Most Contractors Will Recommend
Experienced foundation contractors typically recommend the method that best fits the specific application rather than having a strong preference for one over the other. Be cautious of a contractor who pushes one method on every job regardless of conditions.
Common project combinations:
- Push piers on the main perimeter + helical piers on a settling porch attached to the same home
- Push piers for most of the foundation perimeter + helical piers for interior settling beneath the slab
- All helical if the structure is lighter or access is limited throughout
Questions to Ask Your Contractor
- Why are you recommending this method for my specific application?
- If I have both perimeter and interior settling, what method would you use for each?
- Is the pier count the same regardless of method, or does the installation approach change the number needed?
- Are the warranties equivalent between the two methods you offer?
- What soil conditions in my area favor one method over the other?
A contractor who answers these questions specifically - rather than with a generic sales pitch for one system - is worth trusting with the project.