An Ankeny body shop foreman called us in September asking whether he could put a new hydraulic lift automotive on his existing 1985 shop slab or whether he needed to tear out concrete first. His restoration work runs to classic muscle cars, occasional trucks, and one memorable Model A that spent three months in his metal shop. His current setup was two 1990s-era two-post lifts of unknown pedigree, and one had started leaning. This article is the buyer’s guide we walked him through, focused hard on concrete slab thickness, rebar, PSI, and the honest reality of installing a hydraulic lift automotive on an older shop floor.
ALI Gold asymmetric two-post lifts for restoration and body-shop work, with slab assessment included on Ankeny-area jobs. Call 800-674-9302 for a written total-price quote.
What Slab Do You Actually Have
His shop was built in 1985 as a general auto repair facility, converted to body work in the late 1990s. Nobody had a copy of the original slab spec, which is common in older commercial buildings. The city permit office had a general note saying “reinforced concrete” and nothing else. That was our starting point. We ran a core drill at three locations, one at each existing lift and one in an open area where a new lift might land. Slab thickness came back at 5.25 inches, 4.75 inches, and 6 inches. PSI on the cores tested at 4,200 psi, 3,900 psi, and 4,400 psi.
Rebar was present on 16-inch centers in the deeper section and 24-inch centers in the thinner section, consistent with a slab that was poured to different specs across the building. For any hydraulic lift automotive install, ALI requires 4 inches minimum thickness at 3,000 psi minimum for two-post lifts up to 12,000 pounds. His slab passes the minimum, but the 4.75-inch section is close and would give us pause. We recommended he plan on landing new lifts in the 5.25 or 6-inch sections and avoiding the thinner area. Not glamorous, but honest. Core drilling costs a few hundred dollars and eliminates the expensive surprise of a slab that cracks on install day. See our slab requirements article for the full standards reference.
Rebar, Fiber Mesh, and the Reinforcement Question
His slab was rebar-reinforced, which is the older standard for commercial floors. Newer construction often uses fiber mesh or a combination of fiber and rebar, and current best practice for lift installations is #4 rebar on 12-inch centers with a 2-inch cover from the top surface. Slabs with only fiber mesh and no rebar can still support a hydraulic lift automotive if they are thick enough and the concrete is high-strength, but they crack around the anchor bolts more readily than rebar-reinforced pours. The anchor loading matters.
A 12,000-pound two-post asymmetric under maximum load transfers roughly 20,000 pounds of downward force plus significant lateral force through each column base into the anchor bolts. Those anchors are typically 3/4-inch diameter epoxy or wedge anchors, 5.5 inches embedded, torqued to spec. In a rebar-reinforced 5-inch slab at 4,000 psi, that anchoring holds indefinitely with normal use. In a 4-inch fiber-only slab at 3,000 psi, the anchors work initially but the slab can crack around them within a few years under repeated flex loading. For a body shop hydraulic lift automotive doing daily service on restoration vehicles, rebar reinforcement is the safer bet. If your slab is fiber-only and thin, plan for either a slab replacement or an epoxy overlay in the anchor zone. Both add cost, but both are cheaper than a lifted vehicle tipping.
Slab Cracks and Cold Joints
His 1985 slab had several cracks running through it, which is normal for a forty-year-old floor. Most of the cracks were shrinkage cracks, hairline width, cosmetic only. Two cracks concerned us. One ran through the location of his existing leaning lift’s front-passenger column base. That crack had started as a shrinkage crack, and years of cyclic loading from the lift had opened it to about a quarter inch wide with visible edge spalling. That is a signal the slab is failing under the anchor loading. The other concern was a cold joint running the length of the shop where two different pour dates had met.
Cold joints are lines of weakness, and lift anchors installed near cold joints can pull the slab apart at the joint under load. We recommended he plan his new hydraulic lift automotive placements at least 24 inches away from any cold joint or existing crack wider than 1/8 inch. That constraint reduced his usable floor area but eliminated the risk. If your shop has visible cracks or cold joints, walk them before you buy any lift. Take photos, measure widths, note locations. Bring the sketch to your installer. Any hydraulic lift automotive installer worth hiring will refuse to anchor into a compromised slab and will help you plan repairs or alternatives.
The Body Shop Load Question
Body shop work is different from general repair work in ways that matter for lift selection. Restoration jobs frequently involve pulling engines and transmissions, which shifts the vehicle’s center of gravity dramatically. A 3,900-pound Chevelle with the small block pulled becomes about 3,400 pounds with the front way lighter and the rear normal. That kind of weight asymmetry stresses two-post lift arms in ways daily service work does not. We recommended he step up to a 10,000-pound asymmetric two-post rather than a 9,000-pound, specifically for the load margin.
He also does frame work occasionally, which means welding on the vehicle while it is lifted. That requires a lift with proper grounding path and no hydraulic hose runs where welding sparks can reach. Every hydraulic lift automotive we spec for a body shop gets a review of hydraulic hose routing and grounding practice before install day. Not always because the lift design requires it, but because body shop work demands it. His metal shop also does sheet metal fabrication with a plasma table on wheels, and the plasma table gets rolled under a lifted vehicle occasionally for fitting work. That means the raised height needs to be at least 78 inches for the plasma cart to clear. Standard raised height for a 10,000-pound two-post is 75 to 78 inches, borderline for his use. He needed a 78-inch minimum. Small details, real differences.
Installing on the Old Slab
After the core drill data came back, we designed his install to land two new hydraulic lift automotive units in the 5.25-inch and 6-inch sections of his existing slab. Both locations were also away from cold joints and existing cracks. The two 1990s-era lifts he was replacing came out first. Removing an old lift involves cutting the anchor bolts flush with the slab, dropping the columns, and hauling away the equipment. The old anchor holes get filled with hydraulic cement or a structural epoxy, allowing the slab to remain stable. New anchors do not go into the old holes.
New holes get drilled fresh in the location best suited to the new lift geometry, which is rarely exactly where the old lift was. Anchor drilling is done with a rotary hammer to spec depth, cleaned with compressed air and a brush, and either epoxy or wedge anchored based on slab condition. Torque to manufacturer spec, verified with a calibrated torque wrench, documented on the install checklist. All of that took two days for his two-lift install. Concrete cure time on any epoxy anchor is 24 hours before loading. We do not raise vehicles on freshly installed anchors, ever. Any installer who tries to save you a day by loading same-day is either inexperienced or cutting corners you will pay for later. Our two-post install guide covers the sequence.
Cost of Doing It Right
His total project came in on the mid-tier commercial range for two ALI Gold 10,000-pound asymmetric two-post lifts, installed, with core drilling, anchor prep, and 24-hour cure discipline included. Roughly 15 percent more than a bottom-tier quote that skipped the core drilling and would have anchored into his slab wherever the shipping crate landed. That premium bought him written verification his slab could carry the lifts, documented anchor loading, and structural confidence for the next twenty years of restoration work.
Any hydraulic lift automotive install that skips the slab verification is gambling with a customer’s vehicle and a mechanic’s life on incomplete information. We refuse to work that way. Older body shops with unknown slab spec are our specialty because we have seen every variation. Some slabs pass with room to spare and some fail the core drill so badly the customer ends up pouring a new anchor pad in the corner. His slab was the middle case, workable with careful placement. Cost transparency was the other thing he asked for and got. Every line item in his written quote traces to a measurement or a scope item. No surprise charges at install completion. If a competitor quote does not itemize freight, oil, anchoring, and cure time separately, ask why.
What Ankeny Body Shops Should Do Next
Ankeny and the greater Des Moines metro have a lot of older shops built in the 1970s and 1980s with slabs of unknown pedigree. If you are running a body shop, restoration operation, or general auto repair with pre-1995 concrete under your existing lifts, get a slab assessment before your existing lifts fail. A core drill costs a few hundred dollars and takes an afternoon. You will know exactly what you have, and you can plan replacement equipment accordingly. Waiting until your current lift starts leaning, like our Ankeny foreman did, means you are making a purchase decision under pressure with a leaking asset already on your floor.
Better to plan in advance. For any body shop hydraulic lift automotive project we quote in the Ankeny, Waukee, Grimes, Urbandale, or greater Des Moines metro area, we include the slab assessment at no charge as part of the site visit. It saves us both time later and it gives you a defensible written record for insurance and permit purposes. Call 800-674-9302 to schedule. Bring a rough sketch of your shop and a note about the age of the building. That is all we need to get started. First call is always free, no obligation, and we will send you a copy of the buyer’s guide checklist by email after we talk it through.
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