Helical Piers for Foundation Repair: How They Work

Helical piers are steel shafts with helical plates that are rotated into the ground until torque confirms they have reached soil strong enough to carry the load. They cost $700 to $2,500 each, and a full job commonly runs $6,000 to $30,000. They suit lighter structures, tight access, and sites where a push pier rig cannot operate.

What a Helical Pier Is

A helical pier is a foundation support consisting of a steel shaft with one or more helical plates welded near the lead end. It is advanced into the soil by rotation rather than by driving, and the torque required to turn it is recorded as a measure of soil resistance.

That torque reading is the installation’s proof of capacity. The engineer specifies a torque value, the installer stops when it is reached, and the reading is logged. Unlike a driven pile, the pier does not need to hit refusal; it needs to reach the specified torque at the specified depth.

How Installation Runs

The crew exposes the footing, bolts a bracket to it, and positions the torque motor. The first section is advanced, then extensions are added as the pier goes deeper. Each section is coupled with a bolted or welded connection, and the torque is monitored continuously.

When the target torque is reached, the pier is cut to length, the bracket is loaded, and the lift proceeds in the same way as any other pier system. A typical residential pier goes 15 to 30 feet, and the whole installation for one pier takes 30 to 90 minutes depending on soil.

Cost and Job Arithmetic

A job with eight helical piers at $1,400 each:

8 × $1,400 = $11,200

Add engineering at $900 and a permit at $300:

$11,200 + $900 + $300 = $12,400

That sits inside the $6,000 to $30,000 band and is typical for a single-wall repair on a light-frame house.

Helical Versus Push Piers

Push piers are the default for a heavy house on a site with access, because refusal is an unambiguous end point. Helical piers are the default when the rig cannot get to the wall, when the structure is light, or when the soil is consistent enough that torque is a reliable proxy for capacity.

Where Helical Piers Fit Best

They are common on decks, porches, additions, and light-frame houses where the loads are lower and the pier count is modest. They are also used to stabilize retaining walls and to support new construction on sites with poor surface soils.

They are less suitable where the soil contains large obstructions, because the plate can strike a boulder and deflect. They are also less suitable where corrosion is aggressive, such as some coastal or fill sites, unless the pier is galvanized or coated for that environment.

Ask for the torque log. It should show the final torque for each pier and the depth at which it was reached. A log that shows every pier at exactly the same torque and depth is suspicious; real soil varies, and the readings should vary with it. Ask, too, for the engineer’s torque specification and the correlation used to convert torque into capacity, because that correlation is soil-dependent and a reputable installer will have it documented rather than asserted.

A Costed Repair

A 1,300 sq ft cottage has settled along a 32-foot wall. The engineer specifies helical piers at 8-foot spacing:

32 ÷ 8 = 4 piers

At $1,600 each:

4 × $1,600 = $6,400

Add engineering at $800 and interior restoration at 10% to 25%:

$6,400 × 0.10 = $640 $6,400 × 0.25 = $1,600

All-in: $7,840 to $8,800. That is a small job at the bottom of the full range, which is typical for a light house with one affected wall.

The Installation Sequence

1. Get an engineer’s design with pier capacity, torque, and spacing.
2. Confirm the permit and the utility locate.
3. Excavate to the footing and bolt the bracket.
4. Advance the pier sections, recording torque at each stage.
5. Reach the specified torque and depth, then cut and load the pier.
6. Lift to tolerance, lock off, and backfill.
7. Record the torque log and hand it to the homeowner.

When to Choose Something Else

If the house is heavy masonry and the site has access, push piers are usually the better value. If the movement is lateral rather than vertical, neither pier type is the answer, and anchors or straps are. If the soil is so poor that neither system reaches capacity, a different foundation solution may be required.

For the comparison, read push piers versus helical piers and helical pier cost. If the movement is a bowing wall rather than settlement, wall anchors explained covers the correct repair.