Choosing between helical piles and micropiles isn’t about which system is faster or cheaper — it’s about what the ground can actually support. At FSGC, that decision always starts below the surface.
Reading the Ground First
Before anything else, we review the geotechnical report: soil type, depth to solid rock, groundwater, and how much load the foundation needs to carry. If there’s suitable clay and no shallow rock, helical piles are usually a strong fit. If rock sits close to the surface and the loads are heavy, micropiles tend to perform better.
Shallow rock is the biggest factor pushing a project toward micropiles. A helical pile works like a large screw — it gains strength by twisting into the ground until it reaches a target resistance, called torque. If rock is too shallow, the pile can’t reach that torque before it hits rock and stops advancing. Micropiles don’t have that limitation; they’re drilled directly into soil and rock and bonded in place with grout, so they perform reliably even where helical piles can’t get deep enough. In many of these cases, a hollow-bar micropile (a micropile that is installed by drilling and grouting in a single continuous process using a hollow steel bar) offers a fast, dependable way to reach competent rock without the need for a separate casing.
When Two Jobs Happen at Once
Some projects need underpinning and excavation support working together — holding up an existing structure while digging safely alongside it. We’ve handled this on a warehouse expansion, where the existing footing needed support before excavation could begin next door, and on a hospital project, where underpinning prevented settlement while soil was removed nearby — work that grew into a full shotcrete excavation wall, with micropiles tied in as soldier piles.
The building’s height and loading typically decide which system fits. A one-story structure with lighter loads can often use helical piles. A taller building next to a deep excavation usually calls for a cased micropile (a micropile installed with a permanent steel casing left in place for added stiffness and lateral resistance) instead, since it can carry the vertical load of the underpinning while also resisting the lateral pressure from the dig.
Where Helical Piles Add Real Value
When soil conditions cooperate, helical piles install quickly with minimal equipment, and once they reach the required torque, the foundation can be built immediately — no curing time, no extra testing. That speed can translate directly into savings on labor, equipment, and schedule, which is why it’s worth flagging a viable helical option even on projects where an engineer has already specified micropiles.
A Common Misconception
Helical piles are often assumed to be a drop-in substitute for micropiles. They aren’t. Where rock is shallow, they simply won’t reach the depth needed to perform — no matter how fast or economical they are elsewhere. When a client wants to save money with helical piles but the soil says otherwise, we explain what the ground is telling us, price both options honestly, and steer the conversation toward the system that will actually hold up over time — not just the cheapest one upfront.
The Bottom Line
Helical piles and micropiles aren’t rivals — they’re two tools built for different ground conditions. The right call starts with the geotechnical report, gets tested against the building’s loads, and only then factors in cost.
Have a project with tricky subsurface conditions? Loop our team in early — we’d rather help you land on the right system from day one.