How helical piers work
A helical pier looks like a giant steel screw. The lead section has one or more round helix plates welded to the shaft. A hydraulic drive head turns the pier into the soil, and extension sections are added until the helix plates bear on firm material. As it’s installed, the installer records the torque it takes to keep turning. Torque correlates with load capacity, so the installation itself becomes a field test of each pier.
Once a pier reaches its target torque and depth, a steel bracket is fastened to the footing and the load is transferred onto the pier. Depending on the plan, the footing can be held where it is or lifted slightly with hydraulic jacks before it’s locked off.
When helical piers make sense
Helical piers don’t rely on the weight of the house to drive them, which is their big advantage. They’re usually the better choice when:
- The structure is light, such as a single-story wall, a garage, a room addition or a patio cover footing
- Access is tight, such as a narrow side yard or a backyard behind a block wall
- New construction or an addition needs piers placed before the load exists
- Soil conditions call for a pier that can be load-tested as it’s installed
For heavy, settling footings under a two-story home, push piers are often the more efficient choice. Our helical vs. push piers guide compares the two in more detail.
Helical piers and Peoria soils
Peoria isn’t one soil. The USDA’s official description of the Cherioni series, one of the soils mapped in the area, describes shallow soil over a cemented duripan, the hardpan most people call caliche. That can be good news for a pier, because firm bearing may be close. It can also be a challenge, because caliche and gravel can stop a helix before it reaches the planned depth, and a pier that refuses on a thin caliche lens isn’t the same as one bearing on competent material.
That’s why pier layouts are based on site conditions and installation records rather than a fixed depth. In north Peoria, hillside lots in communities like Vistancia were often built on engineered fill, and the pier has to pass through that fill to reach native material. Farther north toward Lake Pleasant Regional Park, rock may be shallow enough that a different approach makes more sense. We’ll tell you which situation you’re in.
Our helical pier installation process
Evaluation and pier layout
We start with floor-elevation readings and a look at the soil, drainage and structure. For structural piering, an Arizona-registered engineer typically prepares or reviews the pier layout and spacing.
Permit
Piering is structural foundation work, and it isn’t on the permit-exempt list in Peoria City Code ยง18-21. Plan on a building permit and an inspection.
Excavation at each pier location
A small hole is dug next to the footing at each pier location to expose the footing face. Landscaping and pavers are set aside where possible.
Installation and torque verification
Each pier is driven to depth and torque, and the readings are logged. If a pier refuses early, the plan adjusts rather than accepting a shallow pier.
Bracket, transfer and backfill
Brackets are attached, the load is transferred and any planned lift is completed, then the holes are backfilled and compacted.
Helical piers for additions, patios and flatwork
Not every helical pier job involves a settling house. We also use them to support patio cover posts, pergolas, room additions and garage extensions, particularly where fill soils make a conventional footing risky. When the issue is a sunken driveway or patio slab rather than a structural footing, concrete leveling with foam is usually the simpler fix.
Helical piers elsewhere in the West Valley
Hillside and cut-fill lots in Anthem share a lot with north Peoria, and helical piers suit many of the patio and addition jobs there. In Goodyear, the Estrella foothills and former farmland near the river floodplains each call for different pier depths, which is why we never quote a pier count before seeing the site.
What a helical pier day looks like at your house
Most homeowners are surprised by how small the footprint is. The drive head mounts on a compact machine or a handheld torque motor, so crews can often work through a side gate without tearing out a block wall. Expect some noise, a few neat holes along the foundation and piles of soil on tarps while the piers go in. Pool equipment, gas lines and irrigation are marked before digging starts, and Arizona 811 is called so buried utilities are located first.
After the piers are installed
Once the load is on the piers, we recheck floor elevations and doors. Cosmetic repairs come next. And because helical piers stop settlement at the footing but don’t change what water does in the yard, we’ll recommend any drainage or irrigation fixes that keep the soil around the rest of the foundation stable.
Helical pier FAQs
What is a helical pier?
A helical pier is a steel shaft with one or more screw-like helix plates near its tip. It’s turned into the ground with a hydraulic drive head until it reaches a verified installation torque, which correlates with load capacity. A steel bracket then connects the pier to the footing so the structure’s weight is carried by firmer soil below.
When are helical piers better than push piers?
Helical piers are usually the better choice for lighter structures, such as single-story walls, additions, garages and patio covers, because they don’t need the house’s weight to drive them. They also suit tight access spots and new work where piers go in before the load exists. Heavy, settling footings often suit push piers instead.
Do helical piers work in caliche?
They can, but caliche and gravel can stop a helix before it reaches competent bearing. That’s why the pier layout, lead section and target depth are chosen from site conditions, and why each pier’s installation torque is logged. If a pier refuses early on a thin caliche layer, the plan is adjusted rather than accepting a shallow pier.
Do helical piers need a permit in Peoria?
Plan on it. Piering is structural foundation work, and it isn’t on the permit-exempt list in Peoria’s adopted building code. Most jobs involve an engineer’s pier layout, a building permit and an inspection. Your contractor should explain who pulls the permit and include that step in the schedule.
