There's a conversation happening inside the helical pile industry that almost never happens in front of the people buying the piles. On one side are manufacturers producing purpose-built pile shafts under quality systems like ISO 9001: traceable mill certificates, documented welding procedures, audited production, and in Canada often a CCMC evaluation behind the system. On the other are fabricators building piles from repurposed oil well casing, particularly in Western Canada and the US oil patch, where decommissioned wells and surplus casing create an abundant, inexpensive supply of genuinely high-grade steel pipe.
Both products get screwed into the ground. Both get called helical piles. Both show up on quotes that owners compare on price. And in installer circles, the debate gets tribal fast. “Those aren't real pile manufacturers” on one side, “we've installed thousands without a failure” on the other.
I think both camps are arguing past the actual issue. This isn't a story about good piles and bad piles. It's a story about three legitimately different products that the market currently can't tell apart, and the goal of this article is to lay out the difference plainly, so that contractors, owners, and engineers can have the conversation with full context instead of slogans.
First, give the casing its due
Let's be clear about what oil well casing actually is, because it's often mischaracterized. This is not mystery pipe. Casing is manufactured to API Specification 5CT, a rigorous oil-and-gas standard with defined grades, where the number is the minimum yield strength in ksi: J55 and K55 at 55 ksi, N80 and L80 at 80 ksi, P110 at 110 ksi for deep, high-pressure wells. These pipes are engineered to survive conditions far harsher than anything under a building, including crushing formation pressures, torque, temperature, and corrosive downhole environments, and higher product specification levels under API 5CT carry testing and documentation requirements that are, frankly, as demanding as anything in conventional structural steel supply.
Now compare that to what purpose-built helical piles are typically made from: round hollow shafts to ASTM A500 Grade C or CSA G40.21 structural steel, with minimum yields generally in the 44 to 60 ksi range, and helix plate commonly specified as G40.21 44W or 50W. Read that again next to the API grades. Even the low end of oilfield casing, J55, is comparable in strength to typical purpose-built shaft steel, and L80 or P110 substantially exceed it. On paper, casing isn't the discount steel in this conversation. It's frequently the stronger pipe.
And reusing oilfield tubulars as piling isn't some back-alley improvisation, either. It's been done at serious scale on serious projects. The P&J Live arena in Aberdeen sits on repurposed oil and gas tubulars used as piling, a documented, engineered choice with real embodied-carbon savings attached. Surplus or cut-off casing that was never run downhole is, for practical purposes, just high-grade structural pipe at a good price. There is nothing inherently wrong with putting it in the ground as a pile.
The entire question, the only question, is service history.
Three products, not two
So the honest taxonomy isn't “real piles versus oil pipe.” It's three categories:
New, purpose-built piles. Shafts and helices to ASTM A500 / CSA G40.21, produced under a documented quality system, often with a CCMC evaluation or equivalent behind the assembled product. Known steel, known fabrication, no history.
New-surplus casing. API 5CT pipe that was manufactured for a well but never run downhole. Known grade, mill certs typically available, no service history. Mechanically this is simply high-strength structural pipe; the main difference from the first category is which standard it was born under, and that the welded pile assembly (helix attachment, couplings) depends entirely on the fabricator's shop practices rather than an evaluated system.
Pulled casing. Pipe that spent years downhole and was retrieved, cleaned, and cut for reuse. The grade is still known; it's stamped and specified. What's unknown is what its working life took out of it.
Most of the industry's shouting collapses the second and third categories into one, and that's where the conversation goes wrong. They are very different products carrying very different questions.
The thought experiment that cuts through it
Forget oil wells for a second. Imagine a purpose-built helical pile from a certified manufacturer. It's installed under a structure, carries load for ten years, and is then extracted and trucked to a new site to be reused.
Would you design that pile to 100% of its day-one capacity?
Most people, whether contractors, owners, or engineers, instinctively hesitate. Ten years of sustained load. Installation and extraction torque, twice. Possible corrosion below grade where nobody could see it. Maybe someone welded a new bracket on after it came out. Nothing about that pile is necessarily wrong. But would you stake the full original number on it without looking? Probably not. You'd want an inspection, or you'd carry some margin, or both.
That's the pulled-casing question in its entirety. The steel grade isn't the uncertainty. An engineer designing with pulled L80 knows they have 80 ksi minimum yield pipe. From a limit states perspective, the design question is not “is this L80?” but “what fraction of the original section and toughness can I reliably count on today, given incomplete information about past loading and environment?” Possible wall loss, localized pitting, residual stresses from downhole service: none of it visible from the outside.
And engineering has a standard, honest tool for exactly that situation: design further from the limit. A higher factor of safety, lower utilization, a requirement that the pipe arrive in visibly sound condition, spot wall-thickness checks where the stakes justify them. This is not a workaround. Codes and assessment practice for existing structures handle incomplete information exactly this way, through conservative assumptions plus selective inspection. It's engineering working as intended.
One more piece of context that cuts in casing's favour: the long-term corrosion picture underground is better than most people assume. Decades of buried-steel research going back to the NBS studies show that section loss in undisturbed, de-aerated native soil at depth is small. The vulnerable zone is the upper shaft in disturbed fill and fluctuating water tables, and that's true whether the pipe began life as casing or as structural tubing. Service history is a question about the pile's past; below grade in native soil, its future is largely the same story for everyone.
When the history matters, and when it barely does
The reason this debate can't be settled with a blanket rule is that risk is always consequence multiplied by uncertainty, and the consequence side changes completely with the application.
A residential deck on pulled-casing piles, installed clean and to torque, likely utilizes a small fraction of that 80 ksi pipe's capacity. The realistic risk is modest, and the cost savings are real and legitimate. A house? Now the consequence is higher and the questions deserve more rigor, though with verified grade, a condition check, and appropriate design margin, it can still be an entirely defensible choice. Telecommunications towers, transmission structures, anything with sustained tension, cyclic loading, and real consequence of failure? There, the unknown-history question carries genuine weight, the inspection and testing burden should rise to match it, and the owner deserves to be part of that conversation rather than discovering the material provenance never came up.
Same pipe. Same history. Three completely different risk conversations. Anyone selling you a one-size-fits-all answer, in either direction, is skipping the part that matters.
Three value propositions, honestly priced
Which brings us back to the certified manufacturers. An ISO 9001 shop selling new, evaluated, purpose-built piles isn't selling the same thing as a fabricator selling new-surplus L80, and neither is selling the same thing as a yard moving pulled casing. That's fine, as long as everyone knows which one they're buying. One product comes with documented provenance, an evaluated assembly, and no history question. One offers stronger-than-typical steel at lower cost with the fabrication quality question attached. One offers the deepest savings carrying an uncertainty that is perfectly manageable in the right applications and worth real scrutiny in others.
The problem isn't that all three exist. The problem is when they're quoted side by side as interchangeable and the only visible difference is price. At that point the buyer isn't choosing between value propositions. They're choosing blind. And the quiet cost shows up anyway: where provenance isn't disclosed, careful engineers add margin to cover what they can't verify. The foundation wasn't as cheap as the quote suggested; the cost just moved somewhere the buyer couldn't see it.
Disclosure fixes nearly all of this. An installer who says “these are repurposed API L80 casings, here's the condition check we do, here's why that's appropriate for your project, and here's the savings you're getting” is doing right by everyone, and frankly demonstrates more competence than one who simply never mentions it. The red flag was never the material. It's the silence around it.
What anyone can ask
You don't need an engineering degree to navigate this. A handful of questions does it: Is the shaft new purpose-built pipe, new-surplus casing, or pulled casing? What grade? There will be an answer, because it's specified, whether that's A500 Grade C or API L80. For pulled material, what condition verification was done? What does the design assume about it, and what warranty stands behind the installed pile? Are torque records being kept? A good installer in any of the three camps answers these in thirty seconds. The answers tell you far more than the price difference does.
Where this should land
Nobody needs evaluated, ISO-certified production for every deck pile; that would just tax low-risk work for no benefit. And nobody should be putting critical infrastructure on steel with an undisclosed service history. Between those endpoints sits most of the industry, and the territory doesn't need regulation or finger-pointing to become navigable. It needs three things stated on every quote and drawing: which of the three categories the shaft is, what grade it is, and, for pulled material, what was done to verify its condition. That's it. Plain disclosure, matched to application, with the price difference allowed to mean what it actually means.
For readers who want the full framework rather than the argument, this article is accompanied by a free PileConnect practice document, PCS 101:26, Reclaimed and Surplus Oil Country Tubular Goods as Helical Pile Shaft Material: Classification, Inspection, and Design Provisions, available at pileconnect.com/codes-and-standards. It sets out the material categories, inspection levels, default design values, and disclosure requirements described here in a form that engineers, owners, and building officials can adopt on real projects.
The fabricators doing honest work with recycled casing have nothing to fear from that world. Neither do the certified manufacturers. The only business model that suffers is the one built on nobody asking the question, and that's a business model the industry is better off without.
Cory Goulet, P.Eng., is a structural and geotechnical engineer specializing in helical pile design, and the founder of PileConnect.