Underpinning Method
Helical Piers in Sioux Falls, SD
A helical pier is a steel shaft with one or more helix-shaped plates welded near its tip. A hydraulic torque head screws it into the ground like a giant wood screw. Because the resistance to turning correlates with the soil's capacity, the installer knows what the pier will hold at the moment it is installed rather than hoping it holds later.
How helical piers work
The helix plates do the work. As the shaft turns, each plate advances into undisturbed soil and generates bearing capacity from the soil above and below it. Extensions are added until the plates are seated in a stratum that resists turning at the required torque.
That torque relationship is the defining advantage of the system. For a given shaft configuration, installation torque multiplied by an established capacity factor gives an estimate of the pier's ultimate capacity. Every pier is effectively load-tested as it is installed, and the number is recorded.
Once the pier is at capacity, a bracket connects it to the footing, and the structure's load transfers from the soil beneath the footing into the pier and down to the helix bearing depth.
Where helical piers fit best
- Lighter structures — single-storey homes, additions, sunrooms, porches, stoops and decks — where there is not enough building weight to drive a push pier.
- New construction, where there is no existing structure to react against at all.
- Sites with restricted access, since smaller machines and even handheld drive heads can install them in tight side yards and inside basements.
- Projects where documented per-pier capacity verification is a requirement of the engineer or the permit.
- Tiebacks for laterally displaced foundation walls, installed horizontally into competent soil beyond the failure zone.
- Situations where minimising vibration and spoil matters.
Reading a helical pier proposal
The proposal should state the shaft size, the helix configuration, the design working load per pier, the factor of safety, and the target installation torque. Those five numbers together define what you are buying.
It should also state a depth allowance and a per-foot rate beyond it. Helical pier depth is genuinely unknown until the pier is turning, so a proposal without an overage rate is either incomplete or is padding the base price to cover the risk.
Finally, it should promise you the installation log: pier by pier, final torque, final depth. That log is the evidence the design capacity was achieved, and it is documentation you keep for resale.
Side by side
| Consideration | Helical piers | Push piers |
|---|---|---|
| Installation | Rotated into the soil with a torque head | Hydraulically driven in straight sections |
| Capacity verification | Installation torque, measured per pier | Driving pressure at refusal, per pier |
| Structure weight needed | None — torque comes from the machine | Required, as reaction for driving |
| Typical use | Additions, porches, light homes, new build, tiebacks | Heavier existing homes, masonry, multi-storey |
| Access | Small equipment and handheld heads possible | Needs excavation and hydraulic ram at each location |
| Vibration | Low | Low, but with higher localised force on the footing |
Helical pier installation
Step 1
Design
Loads are calculated, pier spacing and capacity are specified, and shaft and helix configuration are selected — ideally by a structural engineer.
Step 2
Excavation
A pit is opened at each location to expose the footing and give the drive head room.
Step 3
Advancement
The lead section is turned in, extensions are added, and torque is monitored continuously until the target is reached at or below design depth.
Step 4
Bracket and load transfer
A foundation bracket is fitted to the footing, the pier is cut to height, and load is transferred in a controlled sequence.
Step 5
Optional lift
Where recovery is part of the scope, jacks raise the section gradually and evenly, monitored across the affected area.
Step 6
Documentation and backfill
Torque and depth are logged for each pier, pits are backfilled and compacted, and grade is restored.
Not sure what you're looking at? Get it assessed.
Describe the symptoms and send photos. You'll get an assessment of what is likely happening and what should be measured before anyone quotes a repair — across Sioux Falls and Southeastern South Dakota.
What drives the price
- Number of piers and design working load per pier
- Shaft size and helix configuration required for that load
- Depth to competent soil, and the per-foot rate beyond the allowance
- Interior versus exterior installation
- Access for equipment, and whether handheld installation is required
- Engineering design and inspection
- Permit costs
- Restoration of concrete, landscaping and irrigation
Cost guide
Helical pier cost
A fuller breakdown of how this work is priced, what is usually bundled in, and what is commonly excluded from a headline number.
Read the cost guideBefore you sign anything
Questions worth asking any contractor
- What is the design working load per pier and what factor of safety applies?
- What target installation torque corresponds to that capacity, and for which shaft?
- What depth allowance is in the price and what is the rate beyond it?
- Will I receive a per-pier torque and depth log?
- Why helical rather than push piers for this structure?
- Who designed the pier layout, and is an engineer signing off?
Sioux Falls, SD
Helical piers on Sioux Falls properties
Attached elements built on shallower footings — porches, stoops, sunrooms, garage additions — are the most frequent candidates for helical piers on local homes, because they are too light to drive push piers and they are the elements most exposed to frost movement.
Tight side yards are common in the older neighbourhoods near the core. Helical installation with compact equipment is often the only practical way to underpin an exterior footing there without dismantling access.
Depth to competent bearing varies across the metro, which is exactly why the torque-verified approach is useful here: the pier stops when the soil says so, not when a table says it should.
See the communities we coverCommon questions
Helical Piers questions
How is helical pier capacity actually verified?
By measuring installation torque. For a given shaft, torque multiplied by an established capacity factor estimates ultimate capacity, so each pier is effectively verified as it is installed. Insist that the readings are logged pier by pier and given to you.
Are helical piers better than push piers?
Neither is universally better. Helical piers suit lighter structures, new construction and restricted access, and they verify capacity by torque. Push piers suit heavier existing structures that can supply driving reaction. The structure and the soil decide.
Can helical piers be installed in winter?
Installation is possible year-round, but frozen ground makes excavation harder and slower, which affects cost and schedule. Where the situation is not urgent, work outside deep frost is usually more efficient.
Do helical piers lift a house back to level?
They can support a lift attempt, but the primary purpose is stabilisation. Recovery is partial in most cases and should be discussed in inches rather than promised as level.
How long do helical piers last?
They are galvanised or coated steel bearing in soil, designed as a permanent element. Service life depends on the coating specification and soil corrosivity, which is a question worth asking the engineer for an aggressive site.
Related reading
Push Piers
The driven alternative, and when structure weight makes it the better fit.
Foundation Underpinning
The full method comparison and how load transfer is verified.
Foundation Settlement Repair
The diagnosis that determines whether piers are warranted.
Bowing Wall Repair
Helical tiebacks used horizontally to restrain a displaced wall.
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