How to add storage capacity without moving
How to add storage capacity without moving
You can usually increase warehouse storage capacity without moving by using more of the building's height, narrowing aisles, storing bulk lines deeper and adding a mezzanine or multi-tier shelving for small parts. Which of these works depends on four facts about your site: clear height, floor capacity, stock profile and the trucks you run, so start by measuring those.
Moving costs a lot more than reworking racking, and a lease or planning timetable rarely matches the growth curve. This guide sets out the options in the order we would test them, with a worked example of how many pallet positions each layout gives, and the safety checks that every change needs.
Key takeaways
- Measure the space you have before buying anything: clear height, empty locations and the gaps above pallets.
- Extra beam levels are often the cheapest capacity, but each one needs clear height, truck reach and frame capacity.
- Narrower aisles and deeper storage add positions per square metre but change trucks, picking speed or selectivity.
- Mezzanines and multi-tier shelving add floor area for small parts and need building approval checks.
- Any change to racking configuration needs a design check, competent installers and new load notices.
Start with an audit of the space you have
The first step is a measured picture of the building and the stock, because most warehouses hold capacity they are not using. Measure:
- Clear height: from floor to the lowest obstruction above the racking zone, which may be sprinkler heads, lights, roof haunches or ducts. Your fire engineer or insurer will set the clearance needed below sprinklers.
- Gaps above pallets: the space between the top of each pallet and the beam above. Large gaps across many bays point to re-profiling.
- Empty locations: a full-looking warehouse can have empty locations scattered across the racking because the beam heights or bay sizes do not suit the stock.
- Stock profile: pallet heights and weights, number of lines, pallets per line and how fast each moves.
- Floor and trucks: slab capacity, floor flatness, truck lift height and the aisle each truck needs.
Our guide to planning a warehouse racking layout covers how these measurements turn into a drawing.
Quick wins before new steel
Some capacity comes back without buying anything. Consolidating part-pallets of the same line frees whole locations. Clearing obsolete and damaged stock, and moving slow lines to the top levels, makes room at the levels that matter for picking. Floor-stacked pallets in aisles and marshalling areas are often a sign the racking is mismatched to the stock rather than too small. Once these steps are done, the audit gives a truer picture of how much new storage you actually need, and the racking you buy is sized for the real stock rather than for clutter.
Use more of the building's height
Adding beam levels is often the most direct gain. If your racking stops well below the clear height, taller frames or an extra level on existing frames can add a full layer of positions without touching the floor plan.
The worked example shows the scale of the gain, but each extra level has to pass four checks. The frames must carry the extra load at the new beam spacing. The floor must carry the higher footplate loads. Your trucks must lift to the top beam with the residual capacity the pallets need. And there must be clear height above the top pallet for sprinklers and handling. Any change in beam levels also means new load notices; HSE guidance expects racking to carry a clear notice showing the maximum load (SEMA, load notices).
Narrow the aisles
Aisles take a large share of a racked floor, so narrowing them adds positions per square metre. Moving from counterbalance trucks to reach trucks, or from reach trucks to very narrow aisle (VNA) trucks, frees floor for more runs.
In the worked example, a VNA layout gives around 40% more positions per level than a wide-aisle counterbalance layout on the same floor. The trade-offs are real: VNA needs specialised trucks, guidance rails or wire guidance, very flat floors and transfer aisles at the run ends. BS EN 15620:2021 sets the clearances and tolerances that racking must meet for the trucks that serve it (BSI, BS EN 15620:2021). Our guide to warehouse aisle widths for each forklift type explains the aisle each truck needs, and our narrow aisle pallet racking is built to the tighter tolerances these layouts need.
Store bulk lines deeper
If you hold several pallets of the same line, you do not need every pallet to be reachable from an aisle. Double-deep racking stores two pallets one behind the other, while drive-in, push-back and pallet live racking store lanes several pallets deep. Each removes aisles and adds positions, at the cost of selectivity: you can no longer reach every pallet directly.
The rule of thumb is to match depth to pallets per line. Lines with many pallets and slow turnover suit drive-in. Lines that need first in, first out suit pallet live. Our guide comparing drive-in, push-back and pallet live racking covers the choice, and the full range is in our high-density racking category.
| Option | Where the capacity comes from | Selectivity | Truck change? | Main checks |
|---|---|---|---|---|
| Extra beam levels | Unused height | Unchanged | Sometimes, for lift height | Frame capacity, floor, sprinklers |
| Re-profiled beam levels | Gaps above pallets | Unchanged | No | Frame capacity at new spacing |
| Reach truck aisles | Narrower aisles | Unchanged | Yes, from counterbalance | Floor, aisle clearances |
| VNA aisles | Much narrower aisles | Unchanged | Yes, VNA trucks | Floor flatness, guidance, transfer aisles |
| Double deep | Half the aisles | Reduced | Yes, extending forks | Stock profile |
| Drive-in or push-back | Aisles removed in blocks | Low | Usually no | Pallets per line, pallet quality |
| Mezzanine or multi-tier | New floor area | Unchanged | No | Building approval, fire, access |
Re-profile beam levels to match your pallets
Beam heights set when the racking was first installed often no longer match the stock. If most pallets are now lower than the openings, closing up the beam levels can create room for an extra level within the same frames. The audit of gaps above pallets tells you whether this is worth doing.
Re-profiling is a design change, not a maintenance task. Frame capacity depends on the distance between beam levels, so moving beams changes what the frame can carry. The new arrangement must be checked against the load tables, carried out by competent installers and finished with updated load notices. HSE's warehousing guidance, HSG76, is the starting point for how racking should be installed and maintained safely (HSE, HSG76).
Add floor area for small parts
Pallet racking is the wrong tool for small, hand-picked items. Moving those lines onto longspan shelving, a multi-tier shelving system or a mezzanine floor adds pick faces and frees pallet positions on the main floor. Multi-tier shelving uses the shelving structure itself to support walkways, while a mezzanine is a separate structural floor that can carry shelving, packing benches or light storage.
Both add floor area inside the building, so they raise questions about structure, fire safety, escape routes and access. Our guide to mezzanine floors and UK Building Regulations covers the approvals to expect.
Keep every change safe and compliant
Capacity projects tend to add load, height and traffic, and each of those affects racking safety. Before work starts, make sure that:
- the revised layout and configuration are checked by the racking designer;
- installers are competent, usually shown by SEIRS cards, and work from the drawing, since even small deviations from the design intent can affect structural integrity (SEMA, guide to storage equipment installations);
- load notices are updated for every changed bay;
- rack protection is added where new aisles or truck types create new impact points;
- the changed racking is inspected under your regime. BS EN 15635 covers the use, inspection and maintenance of steel storage equipment (BSI, BS EN 15635).
Frequently asked questions
Can existing racking be made taller?
Sometimes. Taller frames can replace existing ones, or extra levels can be added if the frames, floor, trucks and clear height allow. A design check against the load tables decides it.
Will narrower aisles slow down picking?
Not necessarily. Reach and VNA trucks are built for narrow aisles, but VNA layouts need transfer aisles and can bottleneck at busy times, so model your peak throughput first.
Can you match our existing racking?
We make racking to our own profiles. Mixing components from different systems is not recommended without a design check, so we usually quote complete new runs or replacement frames and beams.
How much extra capacity can we expect?
It depends on your building and stock. The worked examples here show the scale of change from height and aisle width; a layout drawing for your floor gives the real figure.
Send us your floor plan, clear height and stock profile, and we will return a layout drawing showing the positions each option gives in your building.
