How Each System Works
Both pier types solve the same problem: a foundation that has settled into soft or failing soil needs to be transferred to more stable ground deeper down. The difference is in how they get there.
Helical Piers
Helical piers look like large metal screws. They have helical (spiral) plates welded onto a central steel shaft, and contractors screw them into the ground using hydraulic torque motors attached to excavating equipment. The screw mechanism pulls them deeper as they rotate, which means installation doesn't rely on the building's weight at all.
Because they're screwed in rather than driven, helical piers work well in loose or variable soils where a driven pier might struggle to maintain pressure. Contractors also use them in situations where there isn't enough structural load to drive a push pier, like a crawl space foundation or a lightweight porch addition. The Geo-Engineering community's deep foundation resources note that pier selection depends heavily on load conditions and soil profile, not just installer preference.
Push Piers
Push piers (also called resistance piers or steel push piers) are driven straight down using hydraulic rams. The hydraulic force pushes the pier through the soil, and driving stops when the pier hits bedrock or dense load-bearing soil with enough resistance. The whole system uses the weight of the building itself as a reaction point.
That last part matters. The building has to be heavy enough to resist the hydraulic force during installation. For most full basements and concrete slab foundations, that's not an issue. But for lightweight structures, there may not be enough load to drive a pier to proper depth, which is where helical piers have a real advantage.
Side-by-Side Comparison
When I was helping Greg collect quotes, the numbers were pretty consistent across the three contractors he talked to.
| Factor | Helical Piers | Push Piers |
|---|---|---|
| Cost per pier (installed) | $1,500 to $3,000 | $1,800 to $3,500 |
| Typical pier count | 6 to 12 | 6 to 12 |
| Total project range | $9,000 to $36,000 | $11,000 to $42,000 |
| Load requirement | Low to moderate | Moderate to high |
| Best soil type | Variable, loose, or soft | Dense load-bearing layer required below |
| Crawl space use | Common | Less common |
| Full basement use | Works, less typical | Standard choice |
Greg ended up with 8 push piers at $2,200 each, so about $17,600 total. That was mid-range for his situation: a 1,800 square foot split-level with a full basement and significant settlement on one corner.
Which Is More Common for Basement Foundations
For typical residential basement foundations, push piers are what most contractors recommend. The reason is straightforward: a full basement has plenty of weight to drive piers efficiently, and push piers tend to reach load-bearing material more predictably in many soil types.
Helical piers show up more often in specific scenarios. Crawl spaces and pier-and-beam foundations are common applications. So are situations where the contractor needs to work in confined spaces or where soil variability makes consistent push pier driving unreliable. The FEMA's foundation repair guidance documents discuss both systems in the context of residential foundation stabilization.
Greg's corner settled because a downspout had been directing water against his foundation for years. Once the soil got saturated repeatedly, it compressed. His contractor found load-bearing soil at about 22 feet down, which is within normal range for push pier installation in our area of Ohio.
Questions to Ask Any Contractor
The contractor's reasoning matters more than the system they recommend. You want to understand why they're recommending what they're recommending for your specific soil and load conditions.
Ask them: What are their torque readings showing during test installation? How deep do they expect to reach load-bearing material? What's their warranty on both the piers and any lifting work? Can they explain what they know about soil conditions in your area?
A good contractor should explain the tradeoffs without dismissing the alternative. If someone can only explain why their preferred system is great but can't articulate why the other might work in different conditions, that's a yellow flag. Greg's second contractor could explain both clearly, which partly influenced who he hired.
The Lifting Question
Both systems can potentially lift the structure back toward its original elevation. This is called underpinning with lift. In practice, how much lift you actually get varies quite a bit. Some foundations can be brought back to within a fraction of an inch of original grade. Others can only be stabilized at their current position without much lift, especially if attached structures or utilities would be stressed by movement.
If lift matters to you, whether it's to close gaps around door frames or level a visibly sloped floor, make sure you discuss realistic expectations before signing anything. Get the contractor to put their expected outcome in writing. "Stabilization" and "potential lift to original grade" are different outcomes and shouldn't be treated as the same thing in a quote.