Repair methods

Helical piers for foundation repair

A helical pier is a large screw turned into the ground by machine. That single difference from a driven pier — rotated rather than pushed — is what lets it work under light structures, in spaces nothing else fits, and with a capacity number recorded at every location.

What it is

A steel shaft, square or round, with one or more helical plates welded near the lead end. A hydraulic torque motor rotates it into the soil; the plates pull it down and, once installed, provide the bearing area that carries the load. A bracket ties the head of the pier to the foundation above.

The number and diameter of plates is a design decision, not a fixed product: more or larger plates give more bearing area for softer soils, fewer or smaller for denser ground where the pier needs to advance.

The torque reading — the part worth caring about

Most of foundation repair is professional judgment. Helical piers are the exception that produces a number.

There is a well-established relationship between the torque needed to advance a helical pier and the capacity that pier will have once loaded. The installer can therefore watch a gauge, record a value at each location, and compare it against what the design requires — an in-place verification at every single point rather than an inference from a soil report and a few test holes.

Ask whether torque logs are included in the deliverables. A contractor who records and hands them over is giving you evidence you can show an engineer, a buyer, or a second opinion. One who does not is asking you to take the installation on faith — which may be perfectly fine, but it is worth knowing which you are buying.

Where helicals are the right call

  • Light structures. Porches, additions, stoops, single-story sections — anywhere there is not enough weight for a push pier to drive against.
  • Tight access. Compact equipment, sometimes through a garden gate or inside a crawl space, where a larger rig cannot physically reach.
  • Interior work and crawl spaces, for the same reason. More on crawl space repair →
  • New loads. Supporting an addition, a deck, or new construction on poor soil — helicals carry load immediately without a cure period.
  • Where vibration is a concern, near fragile finishes or sensitive neighbors.
  • Where per-point verification matters — the torque log again.

The expansive clay caveat

Ask this one directly in Texas

Two things need addressing when helicals go into expansive clay. The plates must bear below the active zone — the depth over which the soil shrinks and swells with the seasons — or the pier is founded in exactly the material causing the trouble. And swelling clay can grip the shaft and try to lift it, which is why designs here sometimes sleeve or otherwise isolate the shaft through that zone. Both are routine for a contractor who works this ground regularly, and both are fair questions to ask. More on Texas clay →

Cost, in general terms

About these figures

Foundation Repair IQ does not quote prices and does not perform repairs. The figures below are general industry ranges published for orientation only — not quotes, not estimates for your property, and not binding on any contractor. Foundation pricing is set by the contractor after an on-site evaluation, and your actual cost may fall outside any range shown here.

Helical piers generally fall in the region of $1,400 to $2,500 per pier installed — typically the most expensive per point of the common methods, reflecting the manufactured product and the equipment. On a Texas slab perimeter where concrete pressed pilings are viable, helicals are rarely the economical choice. Where they are specified it is usually because the situation rules the cheaper options out, not because they were preferred on price. Full cost guide →

Questions worth asking

  • What torque are you designing for, and will I get the logs?
  • What depth do you expect the plates to bear at, relative to the active zone?
  • How are you handling shaft grip in swelling clay?
  • Why helicals here rather than pressed pilings or push piers?
  • Are you stabilizing or lifting, and how much recovery is expected?
  • What does the warranty cover, and does it transfer to a buyer?

Questions about helical piers

What is a helical pier?

A steel shaft with one or more helical plates welded to it — essentially a large screw pile. It is turned into the ground by a hydraulic torque motor rather than pushed, and the plates pull it down as it rotates while also providing the bearing area that ultimately carries the load. A bracket connects the installed pier to the foundation. They are also called helical piles, screw piles or anchors, and the same product is used both to underpin existing foundations and to support new construction.

How are helical piers different from push piers?

Two differences that matter. First, installation: push piers are driven using the weight of the building as the reaction force, while helical piers are screwed in by a machine and need no structural weight at all. That makes helicals the option for light structures where a push pier could never reach refusal. Second, verification: torque during installation correlates with capacity, so a helical pier is effectively load-tested as it goes in and the installer can record a number. A push pier demonstrates capacity by reaching refusal against the building's weight, which is a different kind of evidence.

Why does the torque reading matter?

Because it converts installation into measurement. There is an established relationship between the torque required to advance a helical pier and the capacity that pier will have, so the installer can record a value at each location and compare it against what the design calls for. It is one of the few points in foundation repair where you get a per-unit number rather than a professional judgment. Ask whether torque logs are provided — a contractor who records them is offering you evidence, and one who does not is asking for trust.

Are helical piers better than push piers?

Neither is better in the abstract; they suit different situations. Helicals win where there is insufficient structural weight to drive against, where access is tight enough that only small equipment fits, where installation needs to be quick and low-vibration, or where measurable capacity at each point is valuable. Push piers win where the structure is heavy and competent bearing is deep. A contractor who only ever proposes one of them, regardless of the site, is telling you about their equipment rather than your ground.

Can helical piers be installed in tight spaces?

Yes, and it is one of their main advantages. The torque head can be mounted on compact equipment — including machines that fit through a standard gate or work inside a crawl space — so helicals are often the practical option where a larger rig simply cannot reach. That makes them common on interior work, in crawl spaces, on zero-lot-line properties, and in courtyards or side yards too narrow for anything else.

Do helical piers work in expansive clay?

They can, with a design caveat specific to clay. The helical plates need to bear below the active zone — the depth over which the clay shrinks and swells seasonally — or the pier is anchored in the very material causing the problem. There is also a phenomenon worth knowing about: expansive clay can grip the shaft and lift it as the soil swells, so designs in clay sometimes use sleeving or other detailing to isolate the shaft through the active zone. This is a question worth asking directly in Texas.

Helical piers by area

Whether a helical pier is the right support method depends almost entirely on what is under the house. These pages cover where it fits locally.

Local guide

Fort Worth

Tarrant County has sandy soil, shallow rock and deep clay inside one county line, and a helical pier is the right tool in only one of them. Where you are decides the method.

Read more →

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