If your warehouse is running out of room and you're staring at a wall of shelving full of small parts, you have two options: get more building, or get more out of the building you already have.
When we talk to growing companies, this is often the issue they are trying to solve for. Usually, they ask, "How many shelving sections can a Vertical Lift Module (VLM) actually replace?" The answer is more than you might expect, and the floor space you get back opens up real operational possibilities.
In this article, we'll cover where warehouse racks and shelving work, and where they don't.
We’ll also cover:
Looking for hard numbers? We’ve got real data and examples to help you on the path toward making the most of your warehouse storage.
Warehouse racks and shelving are some of the most flexible, cost-effective, and widely used storage mediums in warehousing.
Even those running automated systems still rely on racks for some portion of their inventory.
Racks earn their place when you need to store:
For these use cases, racks and shelves are practical, durable, and straightforward to manage. The problem shows up when you start using them for everything, especially small parts, high-SKU environments, and fast-moving inventory.
The core limitation of traditional warehouse shelving is that it spreads storage horizontally.
Every shelf section claims more of your floor space, and the empty air between the top of your racks and your ceiling represents capacity you’re paying for but not using.
In a facility with a 25-foot ceiling and 12-foot racks, roughly half the building’s vertical cube is wasted.
A Vertical Lift Module, or VLM, is a tall, enclosed automated storage unit that uses almost every inch of your ceiling height. Trays of inventory are stored in vertical columns on both sides of a central extractor. When a picker needs an item, they request it at a touchscreen, and the extractor retrieves the correct tray and delivers it to an ergonomic access opening at waist height. That means no climbing, searching, or walking the aisle.
The result is storage that grows up instead of out, converting the wasted vertical cube above your warehouse racks into active, accessible inventory.
Replacing your warehouse shelving with vertical solutions can offer real space savings.
For example, a 20-foot ceiling eliminates 45-49 shelving sections, saving roughly 83% of floor space. Within a warehouse with a 25-foot ceiling, a single VLM installation can eliminate up to 65 shelving sections and reclaim more than 600 square feet of floor space. At 40 feet, you are looking at up to 100 sections, and nearly 1,000 square feet returned to productive use.
The higher your ceiling, the more dramatic the math gets. But even at a modest 15-foot ceiling, replacing 30+ sections of shelving with a VLM cuts your small parts footprint by more than three-quarters.
Here's exactly how many shelving sections a single Vertical Lift Module can replace at common ceiling heights (and how much floor space comes back).
| Ceiling Height | Eliminated Shelving Sections | Space Savings (sq. ft.) | Space Savings (percentage) |
| 15' | 31-35 | 317-328 | 76% |
| 20' | 45-49 | 461-472 | 82% |
| 25' | 59-65 | 569-616 | 85% |
| 30' | 73-80 | 713-724 | 88% |
| 35' | 87-94 | 821-868 | 89% |
| 40' | to 100 | to 929 | 91% |
All World Machinery Supply is a great example of what happens when shelving reaches its limit and vertical storage becomes the better layout decision.
When All World approached us about consolidating their small parts inventory, we worked with them to determine the right solution. Based on the numbers, All World Machinery installed four Kardex Shuttle VLMs, redesigning their layout around vertical storage.
Here are some other advantages customers have shared with us once they convert traditional shelving to VLMs.
If small parts inventory is spreading across long rows of shelving, floor space disappears quickly. That space could often be better used for production support, packing, staging, kitting, or additional workstations.
A VLM helps you shift storage from horizontal to vertical. Instead of extending your storage footprint outward, you use available overhead space to store more inventory in a much smaller area.
If your SKU count is growing or you routinely carry work-in-process inventory, reclaimed space gives you room to expand capacity inside the same building without moving or leasing additional space.
Adding more shelving can feel like the low-risk option. But before you commit more floor space to static storage, it is worth stepping back and asking whether the same inventory could be stored more densely.
If you are about to purchase more shelving, rework aisles, or dedicate more square footage to small parts, that is a strong signal to compare the cost and impact of a VLM first.
As SKU counts rise, shelving can become harder to manage. Similar-looking parts, inconsistent bin locations, and manual processes can all make errors more likely.
A VLM can help create a more organized storage environment by assigning inventory to controlled tray locations and supporting more consistent picking workflows. For operations struggling with small parts visibility, that structure can be just as valuable as the space savings.
Consolidating storage into a VLM shortens the distance pickers travel and speeds up retrieval times. Higher throughput from the same footprint is one of the most common outcomes customers report after installation.
If your leadership team is discussing a building addition, a new lease, or a facility move, a VLM investment is worth comparing directly to those costs. Reclaiming 76%–91% of your small parts floor space often changes the calculation entirely.
In many cases, recovering floor space inside the current building is more practical than expanding the footprint just to make room for more racks and shelves.
Many facilities have clear height that is not being used effectively. If your building has vertical space available, continuing to add more shelves at floor level may not be the best long-term move.
Did you know you can also build a vertical lift module outdoors?
For greenfield projects, designing vertical storage into the plan from the start allows you to build a smaller building footprint. Smaller buildings mean lower construction costs, reduced taxes, lower utilities, and reduced security overhead every year, indefinitely.
Wondering how much a VLM costs? Our complete Vertical Lift Module pricing guide can help.
Keep traditional warehouse shelving for:
Use VLMs for:
The most efficient operations treat their VLM zone as the hub of daily picking activity, a central ASRS core where high-velocity inventory lives. Pallets and bulk storage operate in supporting zones around it. This layout reduces picker travel, improves accuracy, and makes the entire operation faster without requiring additional floor space.
Compare Vertical Lift Modules vs Modular Drawer Cabinets here.
A VLM can be a strong solution for small parts, high-SKU inventory, and frequently picked items, but that does not mean warehouse racks and shelves stop making sense. In many operations, traditional storage is still the right choice for part of the inventory.
The goal is not to force everything into one storage method. The goal is to use each one where it performs best.
Racks and shelves are often the better fit for inventory that is too large, too heavy, or too awkwardly shaped for tray-based vertical storage. Pallet loads, long materials, oversized cartons, and large assemblies usually belong in more traditional storage systems.
While a traditional VLM might not be the right fit, you might consider a heavy-duty vertical lift module for bulky or extra-long items.
If certain items are rarely picked, dense automation may not be necessary. Slower-moving stock, reserve inventory, and backup materials can often stay in shelving or rack locations without creating a major operational problem.
Some facilities need simple storage for overflow, seasonal demand swings, or temporary inventory increases. In those situations, standard shelving or racks may be the most flexible and cost-effective option.
Not every item needs highly organized, goods-to-person storage. For products that are easy to identify, easy to access, and not picked often, open shelving may be perfectly adequate.
Use this checklist to assess whether your operation is a good candidate for vertical storage:
If you've been relying heavily on traditional racks and shelves, the move to automated vertical storage can feel like a big one — operationally and financially. But size alone isn't the deciding factor.
In a recent survey of Kardex Remstar customers, 56% reported operating with 24 or fewer employees, and many run lean teams of 10 or less. What matters more than your warehouse's size is whether you have the vertical space, the SKU density, and the picking volume to justify the investment.
The best way to understand what a VLM can do for your operation is to walk through your specific floor plan and inventory profile with someone who has seen it done before. Our team offers free site visits to help warehouse and operations managers assess whether vertical storage makes sense — and what the return on that investment looks like in real terms.