If you’ve ever walked through a warehouse, a retail distribution center, or a manufacturing facility, chances are you’ve seen foldable stillage cages stacked high, their sloped sides and rigid frames making them easy to spot. For anyone in the business of moving, storing, or shipping parts, produce, or bulk goods, these cages are a workhorse—they save space when folded flat, keep products secure during transit, and are reusable for years. But one question I get asked almost every day by warehouse managers, logistics coordinators, and even new clients just starting out with these cages is the same: “How many can I stack safely?” Foldable Stillage Cage
As a foldable stillage cage supplier, I’ve spent years answering this question, and it’s not one with a one-size-fits-all answer. A lot of people assume you can just stack as many as you have space for, but that’s a quick way to end up with damaged cages, broken goods, or even workplace injuries. I’ve seen it happen too many times: a manager stacks 8 cages in a tight aisle, the bottom frame bends under the weight, the whole stack collapses, and half a pallet of fragile parts gets crushed. So let’s break this down, talk about the science behind safe stacking, and share the rules I’ve learned from working with hundreds of facilities over the years.
First, let’s start with what makes a stillage cage strong. These cages aren’t just metal boxes—they’re made from galvanized steel, which is coated to resist rust and wear, and their frames are engineered to handle vertical load, which is the weight pushing straight down from the cages above. The key part here is the base: most standard foldable stillage cages have a recessed base with two or four support feet that fit into the base of the cage below it, a design that’s meant to keep the stack from shifting. The side walls and the top edge of the cage are also built to support weight, but the bottom cage in any stack takes the most stress. That’s where a lot of people go wrong—they forget that every cage added on top adds its own weight, plus the weight of the goods inside, all pressing down on the first cage.
Let’s put numbers to that to make it real. A standard 1200x800mm foldable stillage cage, the most common size we supply, weighs around 35 kg (77 lbs) empty. When it’s folded flat, it’s much lighter, but when it’s in use and filled with goods, the average weight can range from 200 kg (440 lbs) for light items like produce or textiles, up to 800 kg (1764 lbs) for heavy parts like metal components or automotive parts. So if you’re stacking four full cages, the bottom one is holding the weight of three full cages plus its own: that’s 3*(200-800 kg) + the base cage’s 200-800 kg, so total 800-3200 kg (1764-7055 lbs) on that lowest frame. That’s a lot of force, and if the cage wasn’t built to handle that, the frame will bend, the welds on the base will crack, or the whole stack will tip.
Now, what determines the actual safe number? It starts with the cage’s rated vertical load capacity. Every foldable stillage cage we supply has a load rating stamped on the base plate—this is the maximum weight the cage can support when it’s the bottom one in a stack. For our standard heavy-duty cages, that rating is 1500 kg (3307 lbs), which means you can stack up to three full cages on top of the bottom one (since 4 cages x 500 kg average per cage = 2000 kg? Wait, no, wait—let’s do the math correctly. Wait, if the bottom cage is rated for 1500 kg, that means the total weight it can hold (its own weight plus all cages above) is 1500 kg. So if each cage is 500 kg when filled, that’s 3 total cages for the bottom one: 500 + 500 + 500 = 1500 kg. Oh right, that’s the right way to calculate it. So that’s three full cages, total four stacked. But if you have our extra-heavy-duty industrial cages, rated for 2500 kg, you can stack up to six full cages (2500 / 500 = 5, plus the base, that’s 6 total). That’s the baseline, but there are other factors that change this.
One big factor I see all the time is how the cages are loaded. A lot of people pile heavy items on one side of the cage, instead of spreading the weight evenly. If you stack two heavy cages on top, and both are loaded with 800 kg of metal parts, all on the left side of the stack, the frame on the left is taking 1600 kg instead of 800 kg, which is way more than it’s designed for. Even if the rated capacity is high, uneven loading can make the stack unstable and damage the bottom cage. I always tell clients: distribute the weight evenly across the base of each cage, avoid overloading any individual cage, and check that the goods inside don’t stick out over the edges—protrusions can get caught on the cage above and knock the stack off balance.
Then there’s the environment. If you’re stacking cages outside in a warehouse yard, exposed to rain, snow, or extreme temperatures, the metal can get weaker over time. Galvanized steel is durable, but repeated exposure to moisture can cause rust, which eats away at the frame and reduces its strength. Cold temperatures too—steel becomes more brittle when it’s very cold, so a stack that’s safe in a warm warehouse might bend or crack in a frozen loading dock. I recommend reducing the number of cages by one if you’re stacking outdoors, and inspecting the bottom cage in the stack every time you restock to check for rust or bent frames.
Another thing: the age and condition of the cages. All metal cages wear out after years of use, even if you take good care of them. Welds can come loose from frequent folding and unfolding, the base feet can get bent when they’re dragged across concrete, and the frame can have small cracks that are hard to see. If a cage is more than 5 years old, or has visible damage, don’t stack as many on top of it. We always tell clients to retire any cage that has a bent base or a cracked weld—even if it still looks like it works, it’s not safe to stack heavy weight on.
Wait, what about folded flat? A lot of people fold their stillage cages when they’re not in use, to save space in storage. How many can you stack then? That’s a different story. When folded, the cages are much lighter and take up less space, but their structure is different—they’re folded flat, so the support feet are tucked in, and the frame is compressed. We don’t recommend stacking more than 5 folded cages at a time, because the top ones can press down on the bottom folded frames and bend them. I’ve seen clients stack 10 folded cages, and when they unfold them, the sides are warped so they can’t stand up straight. It’s better to spread folded cages out on pallets or use a storage rack specifically designed for flat cages if you need to store more than 5.
Let me give you a real example from a client to make this concrete. Last year, a small manufacturing plant in Birmingham ordered 20 foldable stillage cages to transport engine parts. They tried stacking 6 full cages in their narrow warehouse aisle, and a week later, the bottom cage’s base cracked, the top 5 cages fell, and they lost $2,000 worth of parts. When we looked at their cages, they had our standard heavy-duty cages, rated for 1500 kg—so 6 full cages would be 3000 kg total, which is way over the rating. After that, they reduced their stack to 4 cages, and six months later, they haven’t had a single issue. Another client, a grocery distributor, uses our extra-heavy-duty cages for produce—they stack 5 full cages in their cold storage warehouse, and that works perfectly because the cages are rated for 2500 kg, and each cage only holds 300 kg of lettuce or apples.
So putting all this together, the general rule of thumb is:
- Check your cage’s vertical load rating (this will be on the cage’s base plate or in the product spec sheet from your supplier).
- Calculate the total weight of the stack: empty weight of each cage plus the weight of goods in each cage, multiplied by the number of cages.
- Never exceed 70% of the cage’s rated load capacity for the bottom cage—this gives you a safety buffer in case you overload a cage or it gets damaged slightly.
- Reduce the number by one if stacking outdoors or with older, used cages.
- Never stack more than 5 folded cages at a time.
Wait, why 70%? I always say that engineering ratings are the maximum, but real life has variables. A slightly worn cage, uneven loading, a cold warehouse—all of these can add stress, so building in a 30% buffer is a smart way to avoid accidents. I’ve seen engineers confirm this too—when we tested our cages in independent labs, the maximum load they could handle before permanent damage was around 140% of their rated capacity, so using 70% of that as the safe working load makes sense for real-world use.
Now, I know a lot of clients will ask: can I just reinforce the bottom cage to stack more? Technically, you could add steel plates to the base, but that’s more expensive, and it voids the warranty on your cage. The cages are engineered by designers who specialize in logistics storage, and changing the structure can make the whole stack less stable. It’s not worth risking injuries or damage for a couple extra cages—most warehouses have enough space to stack the safe number, anyway.
I also can’t stress enough how important it is to train your team on this. A new warehouse associate might not know that stacking 6 cages is too much, or they might see someone else doing it and assume it’s okay. We always recommend that suppliers include a quick guide to stacking safety with each cage, and hold regular refreshers for your staff. It’s a small step that prevents a lot of problems.
At the end of the day, foldable stillage cages are meant to make your operations easier, not add risk to your workplace. The last thing any of us want is a broken cage, damaged goods, or an employee getting hurt. If you’re not sure what your cage’s load rating is, or you’re planning a new warehouse layout and need help figuring out how many you can stack, that’s what I’m here for. We work with all kinds of facilities, from small shops to large distribution centers, and we can help you pick the right cages for your needs, share the specific load guidelines for your equipment, and even offer tips for safe stacking in your space.
If you’re looking to invest in new foldable stillage cages, or you have questions about your current setup, get in touch with our team to discuss your requirements. We can walk through your facility, talk about your product weight and storage space, and make sure you’re stacking safely without wasting space.
Hanging Cages References
- Material Handling Industry of America. “Best Practices for Industrial Storage & Handling Equipment”. 2022.
- European Committee for Standardization. “EN 15252:2019 – Stillage Cages for Transport and Storage – Safety Requirements”. 2019.
- Smith, J. “Load Capacity and Structural Integrity of Steel Stillage Cages: Field Tests and Case Studies”. International Journal of Logistics Engineering, vol. 14, no. 2, 2021, pp. 89–102.
Taizhou Ziyue Metal Products Co., Ltd.
As one of the leading foldable stillage cage manufacturers in China, we offer a wide range of products with superior quality. We warmly welcome you to wholesale bulk foldable stillage cage for sale here and get quotation from our factory. For price consultation, contact us.
Address: No. 18, Gudun Line, Industrial Agglomeration Area, Fenjie Town, Taixing City, Taizhou City, Jiangsu Province
E-mail: 18352658999@163.com
WebSite: https://www.ziyuemetal.com/
