The Crane Choice That Cost Me a Week and $3,200
In April 2022, I specified a Demag overhead crane for a new fabrication bay. It seemed like the obvious choice—it's what we always used. The problem? The building didn't have the structural steel to support the runway beams.
We found out after the crane was ordered. The result: $3,200 in change fees and a one-week schedule delay. The solution? We should have ordered a Demag gantry crane. It would have sat on the floor, not the roof.
Look, I'm not saying one is better than the other. I'm saying the right choice depends on your building, your budget, and your timeline. Here's how I learned to tell them apart—the hard way.
What We're Comparing (and Why Most Articles Get It Wrong)
Most comparison articles list specs. They'll tell you an overhead crane can lift X tons and a gantry can lift Y tons. That's not helpful. The real difference isn't capacity—it's infrastructure.
The core question: Can your building support an overhead crane, or do you need a self-supporting gantry?
Here are the three dimensions I've learned to evaluate:
- Building structure — Does it exist? Can it carry the load?
- Installation speed — How fast do you need this thing running?
- Flexibility — Do you need to move the crane to different areas?
I used to ignore dimension #1. Assumed every building could take an overhead crane. My $3,200 mistake taught me otherwise.
Dimension 1: Building Structure — Which One Can Your Facility Handle?
The Demag Overhead Crane
An overhead crane needs runway beams bolted to the building's structural columns. This means:
- The building must have steel or reinforced concrete columns
- Those columns must be rated for the combined weight of the crane + hoist + load
- The roof structure must be able to handle lateral forces
I'm not 100% sure on the exact load calculations, but roughly speaking, a 5-ton overhead crane adds about 2-3 tons of dead load to the building structure. That's on top of the live load (the actual lift).
Result: An overhead crane works great if you have a solid building designed for it. If you don't, you're looking at structural reinforcement—which is expensive and time-consuming.
The Demag Gantry Crane
A gantry crane sits on the floor. It has its own legs and a beam across the top. No building attachment needed.
This means:
- You need a flat, level floor with sufficient load-bearing capacity
- Standard industrial concrete slabs (6+ inches) usually work for up to 10-ton capacity
- No structural steel modifications
Result: A gantry crane works in almost any building with a decent floor. It's the safe bet when you're not sure about your structure.
My take: I've seen too many people assume their building can take an overhead crane. It can't always. The gantry is the lower-risk choice for existing buildings.
Dimension 2: Installation Speed — How Fast Do You Need It?
This is where the time certainty premium matters most. In my experience, the difference is significant.
Demag Overhead Crane Installation
A typical Demag overhead crane installation takes:
- Structural assessment: 1-2 weeks
- Steel reinforcement (if needed): 2-4 weeks
- Crane installation and commissioning: 2-3 days
- Total (best case): 2-3 weeks
- Total (with reinforcement): 4-6 weeks
I had a client in January 2023 who needed a 10-ton crane installed in 5 days. We couldn't make the overhead work. The structural assessment alone took 3 days.
Demag Gantry Crane Installation
A gantry crane, by contrast:
- Floor inspection: 1 day
- Crane assembly and setup: 1-2 days
- Load test and commissioning: 1 day
- Total: 3-4 days
We got that client a 10-ton Demag gantry crane delivered and operational in 4 days. Cost us $400 extra for rush shipping. That's $400 vs. a missed $15,000 production deadline. Easy choice.
My take: If you're on a tight deadline, gantry is almost always faster. You're paying for installation certainty, not just the crane itself.
Dimension 3: Flexibility — Do You Need to Move It?
This is the dimension where I've seen people make the wrong assumption—including me.
I initially assumed overhead cranes were more flexible because they cover more area. That's true within their bay. But moving them to another bay? Not happening.
Demag Overhead Crane Flexibility
- Travel range: Full coverage within its runway bay
- Relocation: Extremely difficult. Requires disassembly, structural changes, reinstallation
- Cost to move: 50-70% of original install cost
Demag Gantry Crane Flexibility
- Travel range: Limited to its footprint, but room to room? Possible
- Relocation: A Demag gantry crane with casters can be moved within the facility. Not trivial, but doable
- Cost to move: A fraction of overhead. Usually under $1,000
The surprising conclusion: If you think you might need to rearrange your shop floor layout in the future, the gantry crane is actually more flexible.
I didn't expect that either. Learned it when a client had to move their entire fabrication line six months after installing an overhead crane. The gantry would have saved them $4,000 in reinstallation costs.
When to Choose Each (Based on Real Mistakes)
Choose the Demag Overhead Crane When:
- Your building was designed for it. New construction with crane-ready structural steel = obvious choice.
- You need full coverage of a fixed bay. No other option gives you that range of motion.
- You're not moving. This crane is staying put for 10+ years.
Choose the Demag Gantry Crane When:
- You're retrofitting an existing building. No structural surprises = lower risk.
- You need it fast. Three weeks vs. three days is a real factor.
- You might rearrange shop layout. Flexibility matters long-term.
- Your budget is tight. A Demag gantry is typically 20-30% cheaper upfront.
One more thing: If you are comparing a Demag crane vs a heron crane, it's a different conversation. That's about brand quality and service network. For Demag vs Demag (overhead vs gantry), it's purely about your building and your timeline.
I've made the wrong call twice. Once on the overhead (the $3,200 mistake) and once on the gantry (specified a gantry when we actually needed the bay coverage). Both cost money. Both taught me something. Hopefully, this saves you a similar tuition payment.
