Late last fall we finished an install of automotive two post lifts at a small overlanding and off-road build shop just north of the Iowa-Missouri border, and the whole job hinged on one thing: the slab. The owner was converting the back half of a 40-by-60 pole building into an alignment bay for lifted trucks and prerunners. His concrete looked good from the top, but a two-post loaded with a 7,000-pound rig on 37-inch tires puts different stresses on the floor than the tractor and stock trailer that had lived there before. This case study is about how we made the call on his slab, what we found when we cored it, and how the alignment work has held up in the eight months since. Auto Lift Services covers southern Iowa regularly, and this build was a good reminder of why we insist on slab inspection.
If your shop is planning alignment work on lifted trucks, get the slab and lift right on the first pour. We can help.
The shop, the vehicles, and why a two-post won
The build shop specializes in overlanding conversions for JT Gladiators, Colorado ZR2s, and full-size Ram Power Wagons. Their average vehicle rolls out at 6,800 to 7,400 pounds with tires, bumpers, drawer systems, and a rooftop tent. The owner wanted alignment capability in-house because he was losing three days of build time every time he trucked a rig to Kirksville for a rack-and-pinion alignment after a lift kit install. When he called us about automotive two post lifts, the first question was whether a two-post could even do alignment. Yes, with the right kit, and we explained that a slip-plate turntable setup with the lift at a fixed working height is how most alignment shops handle it. A four-post with cutouts is more common for alignments, but a two-post with the proper accessories works and gives him better access for the suspension work the shop does the rest of the day.
We spec’d a 12,000-pound symmetric with asymmetric arms so he could still park a stock pickup on it without the doors hitting the columns. Overhead configuration. 12-foot column. His ceiling was fifteen and a half feet clear at the ridge, twelve at the sidewalls, so we set the lift closer to the ridge line.
Coring the slab: what we found
Southern Iowa pole barns from the 1990s and early 2000s tend to have four-inch slabs with light welded wire mesh, if they have reinforcement at all. Automotive two post lifts require a minimum of four and a quarter inches of 3,000 psi concrete for the base models we sell, and closer to five inches for the 12K units. We drove down, marked two spots inside the proposed footprint, and pulled two-inch cores with a wet-diamond bit. What came out was four and three-quarter inches of concrete with a clean bottom face and no visible rebar or mesh in either sample. That was borderline, and it made both of us nervous.
The owner had two options. Pour a new pad within the existing slab, saw-cutting a rectangle roughly ten by twelve feet, tearing it out, and dropping in six inches of 4,000 psi with a proper rebar grid. Or use a longer anchor with epoxy set into the existing slab and accept a lower capacity rating. He wanted the full 12,000-pound rating because his heaviest builds were getting close, so he chose the new pad. His concrete guy did it in two days: cut, remove, dig four inches of stone base, tie a number-four rebar grid on twelve-inch centers, pour six inches, trowel finish, cure. Twenty-eight days later we came back to install.
The install: anchor spacing, torque, and level
New concrete gets automotive two post lifts done right, and the difference at commissioning was obvious. Anchors set clean, torque numbers held at the top of spec, and the columns plumbed with almost no shim work. We used the same wedge anchors the manufacturer shipped, five inches long, six per column base, torqued to the exact ft-lb spec on the datasheet and re-checked after twenty-four hours. That re-check is the step every installer skips. New concrete continues to set for weeks after it feels dry, and anchor torque can drop as the base cures around the anchor sleeve. Coming back the next day with a torque wrench takes ten minutes and prevents the loose-anchor complaint that shows up around month three.
We laser-leveled the columns to each other and to the ceiling crossbar, then ran the lift through five full cycles with an empty carriage before we ever put a vehicle on it. The equalizer cables settled a quarter turn of tension in that process, exactly as expected. Automotive two post lifts settle in during the first two dozen cycles, and if the installer does not run empty cycles up front, that settling happens under a customer’s vehicle instead. The owner watched the whole process and asked good questions. He is the sort of shop owner who wants to understand how the equipment works so he can service it himself, and we appreciate that every time we meet it.
Alignment work: the slip plates and the first month
The alignment package we added was a set of front slip plates and rear turntables sized for lifted trucks, which meant wider footprints than the typical car-alignment accessories. He mounted the slip plates on removable stands so he could pull them out for regular suspension work and slide them back for alignments. Total added cost was under $2,000 for the plates, turntables, and a used Hunter WinAlign head that he sourced separately from an equipment dealer in Missouri.
Month one was the trial. He did five alignments the first two weeks: three lifted Gladiators, a stock F-150 for a friend, and one of his own project Colorados. All five passed a check with a portable alignment rig his friend brought over. That was the confidence check he needed. Since then he has done between two and four alignments a week alongside the build work, and the two-post has held level and quiet through all of it. His feedback to us at the six-month check-in was that the automotive two post lifts we quoted gave him roughly twenty-five percent more usable floor time than the four-post his neighbor runs, because he can walk under the vehicle without ducking around a runway. For a build shop working under vehicles all day, that is the whole game.
The rebar question every shop asks
Half the shops we quote ask whether they can skip the rebar. The honest answer: on a new pour for automotive two post lifts, no. On an existing slab that already lacks rebar, sometimes, with epoxy anchors and a lower capacity rating. The rebar in a lift-rated slab does two things. It ties the pad together against the tensile forces the anchors apply when a loaded lift is at height, and it prevents cracks from propagating from the anchor holes outward. Without it, you can pass day-one commissioning and still see cracks radiating from the base plates by year two.
We have watched that happen twice. Both times the owner tried to save $600 on rebar during a $9,000 lift install, and both times the fix ended up costing more than the rebar would have. If your concrete guy tells you rebar is not necessary for a five-inch pad, ask him if he is willing to warranty the slab against anchor-crack failure for five years. If the answer is no, buy the rebar. It is one of the cheapest insurance policies in a shop build. The owner near the Iowa-Missouri border understood this immediately, which is why his pad went in right, and why his lift will still be tight a decade from now.
What we would change if we did this build again
Two things. First, we would have run the electrical to both column locations up front, even though the standard install only wires the passenger side. A future upgrade to a lift with dual-column controls would then be a one-hour swap instead of a day of trenching and chasing conduit through a finished wall. That cost him nothing at pour time and would cost him a real number now. We should have flagged it during the pre-install walk-through, and we have added it to our standard checklist since.
Second, we would have set the columns a foot further apart. The owner mostly runs full-size pickups, and the door-to-column clearance is tight enough that he has to warn customers before they open the driver’s door. Automotive two post lifts come in a couple of standard column spacings, and the wider option would have solved this. We defaulted to the standard because his stated vehicle mix included some Colorados, but in practice the Colorados are the exception, not the rule. Small lesson: ask the shop what they mostly do, not what they occasionally do, and spec to the modal case. That is the guidance we have carried into every quote we have written since.
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