Helical piers, and the paperwork that proves they work

What is helical pier installation?

A helical pier is a steel shaft with one or more helical plates that is rotated into the soil like a large screw until it reaches competent bearing material. Because it is driven by torque rather than pressure, the resistance recorded during installation relates to the capacity achieved - so each pier can be documented individually. That makes it well suited to lighter structures and new construction, where there is no heavy building to push against.

Signs you need helical pier installation

• A settling porch, deck, sunroom or addition that is separating from the main house at the joint
• A light structure - a garage, a single-storey extension, a modular or manufactured home - with a corner that has dropped
• New construction on a site where the good bearing soil is known to be well below the planned footing depth
• An existing structure too light to serve as reaction for a driven system, where a hydraulic method would lift the building before the pier reached depth
• A foundation repair where the engineer's scope calls for documented capacity at each support location
• A site with restricted access, where the equipment has to reach the work through a gate or under a low overhang
• Work planned for a season when driving equipment would tear up a saturated site

Seeing something not on this list? Browse foundation repair problems by symptom →

How helical pier installation actually works

1. 1

   Confirm helical is the right family before choosing a brand

   The method choice follows from the structure's weight, the soil profile and whether documented per-pier capacity is required. Structures light enough that a driven system would struggle for reaction are the classic case. The head-to-head with driven piers is set out on the comparison pages.

   Watch forA contractor whose recommendation matches whatever they install exclusively. Method should follow from the loads and the ground, and the reasoning should be stated in a sentence you can repeat.

2. 2

   Establish the loads and the target capacity per pier

   Someone has to work out what each support location is actually carrying and what capacity each pier must reach. That number is the whole basis for judging the installation afterwards, because torque only means something when compared with a target.

   Watch forA proposal that specifies pier count and spacing without a target capacity anywhere. Without it there is nothing to check the installation record against, and the log becomes a page of numbers with no verdict attached.

3. 3

   Investigate what is under the site

   Helical piers work by reaching soil capable of carrying the load through the helix plates. What that depth is, and whether it varies across the footprint, comes from soil information - a bore log, published local data, or experience on immediately adjacent sites.

   Watch forA fixed shaft length quoted for every location on the property. Bearing depth commonly varies across a single lot, and a fixed length either wastes steel or stops short.

4. 4

   Excavate and prepare each location

   The soil is opened at each support point so the bracket can engage the footing. On a repair, the condition of the footing itself gets assessed at this point - the pier is only as useful as the concrete it will transfer load through.

   Watch forDeteriorated or undersized footings passed over silently. Attaching a bracket to crumbling concrete moves the failure point rather than removing it, and it shows up years later as a support that appears to have done nothing.

5. 5

   Advance the pier and record the torque

   A hydraulic drive rotates the shaft into the ground. As the helix plates enter denser material the resistance rises, and that resistance is monitored throughout. Installation continues until the required resistance is achieved at an acceptable depth.

   Watch forTorque being read off a pressure gauge with no calibration and no written record. Ask how torque is being determined, whether the equipment is calibrated, and whether the readings are written down per pier as the work happens rather than reconstructed afterwards.

6. 6

   Transfer the load through the bracket

   A bracket ties the pier to the footing or foundation wall so the structure's weight is carried by the pier instead of the original bearing soil. Whether the sequence stabilises the current position or attempts to recover elevation is a decision made before this step, not during it.

   Watch forLoad transfer treated as an opportunity to improvise a lift. Elevation recovery has real consequences upstairs and should be a written decision - see foundation leveling.

7. 7

   Collect the as-built record

   When the crew leaves you should hold two documents: a torque log listing each pier with its final resistance and installed depth, and an as-built layout showing where each pier physically is. Together they turn buried steel into something checkable.

   Watch forBeing told the log is internal. It describes work performed on your property and paid for by you, and every serious installer produces one. Put the requirement in the contract rather than requesting it on the last day.

8. 8

   Backfill, reinstate and re-measure

   Excavations are backfilled and compacted, hardscaping and planting are reinstated, and the elevation survey is repeated so there is a documented condition on completion.

   Watch forLoose backfill left to settle on its own, which produces a trench of sunken ground along the wall that directs water straight at the foundation you just paid to support.

What does helical pier installation cost?

Helical pier work is priced largely per pier, so the specified count drives the total. Depth to competent bearing, access for the equipment, and bracket type move the per-pier figure. Small projects such as a settling porch sit far below a whole-side underpinning scheme.

See the full helical pier installation cost guide - by material, size and region →

If the number is the problem, here are the ways people pay for it →