Cantilever Racking for Long Loads: Pipes, Lumber & Steel

Cantilever racking for long loads solves the one problem pallet racks cannot: storing stock where length exceeds pallet footprint. Pipes, lumber, steel sheets, and oversized items sit awkwardly on front-beam racks and create retrieval risk. This blog will walk you through when a cantilever racking system is the right choice, how to size arms and uprights correctly, and what to verify before installation starts.

Why pallet racking fails long loads

A pallet racking system uses two front beams and two back beams per bay to support a palletised load. That works when stock sits flat within the beam span. It stops working when stock extends past the beam length. A 6-metre steel pipe will hang off both ends of a standard 2.7-metre beam bay. A 4-metre lumber bundle cannot be picked cleanly with a forklift from between two uprights.

You can force long items onto pallet racks, but the side effects are predictable: damaged beams from overhang, unsafe retrieval, and wasted vertical space because items that do not sit flat cannot be stacked properly.

Cantilever racking removes the front beam entirely. The load rests on horizontal arms projecting out from a vertical upright column. Nothing blocks the loading face. A forklift or overhead crane can place a full pipe length onto one arm run without a single obstruction in front.

That structural difference drives every design decision that follows.

Cantilever vs pallet racking: the actual trade-off

The comparison is not really close. Each system was built for a different load profile, so choosing between them is an inventory question, not a price question.

Pallet racking wins when stock is palletised, uniform, and within beam span. Selective pallet racking gives direct access to every SKU. Drive-in racking gives density when you store many pallets of the same product. Neither system handles 6-metre galvanised pipe or 4-metre cut steel bar cleanly.

Cantilever racking wins when stock is long, irregular, or bundled. Arms can be set at different heights per column, so one upright can hold thin aluminium extrusions at one level and heavy steel bar at another. Arm length decides the supported overhang. Most cantilever layouts in Singapore warehouses use 600mm, 900mm, or 1200mm arms, with longer arms reducing the rated capacity per arm because of deflection under weight.

One practical test: if your forklift operator has to tilt the load to get it between two uprights, you are using the wrong system. Cantilever racking lets the load go in straight.

For heavy palletised stock that still fits within beam span, a dedicated heavy duty racking system is often the stronger pick. Pallet-based heavy duty systems carry heavy weight per level. Cantilever systems carry heavy weight per arm, with open-front geometry.

Single-sided vs double-sided: pick by layout, not preference

A single-sided cantilever rack has arms projecting from one face of the column. It is designed to sit against a wall or perimeter of the warehouse. You load and retrieve from one side only.

A double-sided cantilever rack has arms projecting from both faces of the same column. It sits in the open floor, similar to a pallet rack run, and stock can be accessed from either side.

The decision is layout-driven. A narrow warehouse with long wall runs benefits from single-sided layouts because no floor area is wasted behind the rack. A wider warehouse with central aisles and forklift traffic on both sides benefits from double-sided layouts because arm positions per column are doubled without doubling the footprint.

Double-sided cantilever is usually more cost-efficient per arm position. Single-sided cantilever is more cost-efficient per square metre of warehouse used, because the back of the rack serves no access function and can sit flush against building structure.

How arm capacity, length, and deflection decide the build

This is where quotation detail matters. Two cantilever layouts with identical bay counts can carry vastly different loads depending on arm class and column specification.

Arm capacity is the first number to confirm. A 200kg per arm class is common for medium-duty storage such as PVC pipe, light timber, and thin sheet stock. A 500kg per arm class suits steel bar, heavier lumber bundles, and pre-cut steel plate at moderate lengths. Heavy industrial storage for thick plate, large-diameter pipe, or full steel coil can require 1000kg per arm or higher. These ratings are not arbitrary. They come from the arm profile, the pin or bolt connection at the column, and steel thickness.

Arm length affects rated capacity because a longer arm bends more under the same load. A 500kg rating on a 600mm arm is not a 500kg rating on a 1200mm arm. Deflection increases with both arm length and cantilever distance from the column face. Suppliers should publish a deflection curve or a derated capacity table for each arm length they offer.

The upright column is the next variable. Column height decides how many arm levels can be set. Column cross-section decides overall stability. Tall columns loaded near the top need wider base plates and more floor anchoring to resist overturning. A cantilever column is effectively a vertical beam with an eccentric forward load, so the base plate does real structural work.

Base plate size is usually standardised per column profile, with hold-down anchors drilled into the warehouse slab. Slab condition matters. A 150mm reinforced slab with no underfloor services is straightforward to anchor. A thin slab above an expansion joint, a sub-floor service trench, or a weak pour area is not. This check belongs in the site visit, before quotation, not after fabrication has started.

Load profiles that change the design: pipes, lumber, steel sheets

Pipes

Pipe storage needs arms long enough to support the full pipe length without excess overhang at either end. A 6-metre pipe stored on 900mm arms with 1.8-metre column spacing gives roughly 600mm overhang per end, which is acceptable for rigid steel pipe but marginal for softer PVC. For pipes that roll, an arm stop at the tip is standard. Without a stop, pipes will walk out under vibration from forklift traffic.

Lumber

Timber storage uses wider arm spacing because bundle widths vary. A lumber yard routinely stores 2.4-metre, 3-metre, and 5-metre lengths on the same rack run, so arm heights are set per length class and column spacing is set to the longest stock. Timber absorbs moisture, so open-side arm racking is preferable to enclosed shelving for airflow.

Steel sheets and bars

Sheet stock is the awkward case. A stack of 2.4 by 1.2-metre steel sheet sits flat across arms but needs wider arm spacing and an arm stop at the front edge. Steel bar behaves like pipe but with higher density per metre, so the arm capacity class has to match stock weight per linear metre, not just bundle weight.

For mixed long stock where some items are short enough for shelving, a longspan shelving system sometimes works better for the short items alongside cantilever for the long items. Treating every long-looking item as cantilever-only stock creates wasted vertical space and higher upfront cost than needed.

Safety checks that prevent arm collapse

Cantilever racking fails in one of two ways. An arm can drop under overload, or a column can overturn if the base plate is poorly anchored or the load is misplaced toward the arm tip.

Load arms evenly across the column. Concentrating weight at the arm tip multiplies the overturning moment on the column. Place heavier stock on lower arms. Lower arms keep the centre of gravity low and reduce overturning risk.

Forklift impact is the single biggest damage source. Cantilever columns sit exposed at aisle ends, and operators approaching from the side can strike the base plate or lower column section. Column guards and base protectors are low-cost components that prevent high-cost repair work. Forklift safety practice around racking systems applies to cantilever layouts more than most because the arms project into the approach path.

Scheduled rack inspection catches arm damage, column deflection, and anchor loosening before failure. The SEMA guide to pallet racking inspections sets out a structured inspection process that applies to cantilever systems as well, covering equipment condition, damage classification, and repair triage. For Singapore warehouses, scheduled rack inspection is the right way to track damage between installation and the next layout change.

Warehouse layouts also need to meet local fire safety rules. The SCDF Fire Code 2023 sets requirements for storage height signage, sprinkler clearance, and aisle access in warehouse occupancies. Cantilever runs sitting under sprinkler heads need the same clearance rules as pallet racks, despite the open-front geometry.

When cantilever racking is the wrong call

Cantilever racking is a specialist system. It loses against pallet racking for any palletised uniform stock within beam span. It loses against boltless shelving for light-duty storage under 100kg per level. It loses against a mezzanine platform when you need high-volume storage of small parts rather than long items.

Warehouses that store mixed long and short stock sometimes buy a full cantilever bank because long items exist in inventory. That is usually a design error. Cantilever racking should cover the long stock specifically. Short stock belongs on the racking system built for it.

If your inventory is 80% palletised and 20% long, you are paying for cantilever capacity for one-fifth of your stock. That may still be the right decision, but the sizing should reflect the 20%, not the 100%.

Conclusion

Cantilever racking is the right answer for long loads and the wrong answer for almost everything else. Get the load profile right, match arm class to stock weight per linear metre, confirm column spacing against your longest stock, and plan base plate anchoring against your actual slab. Everything else flows from those four decisions.

If you are planning a long-load storage layout or reviewing an existing cantilever setup, speak with NTL Storage for a site assessment that covers arm sizing, column spacing, base plate anchoring, and aisle planning before fabrication begins.

FAQs About Cantilever Racking For Long Loads

What is cantilever racking used for?

Cantilever racking is used to store long, heavy, or irregular items that do not fit on pallet racks. Common stock includes steel pipe, timber, lumber bundles, steel bar, sheet metal, and oversized items such as prefabricated frames or extruded profiles. It is standard in steel yards, timber merchants, and MEP contractor warehouses.

How do I choose between single-sided and double-sided cantilever?

Single-sided cantilever racking is built for wall-mounted layouts where stock is accessed from one face only. Double-sided cantilever holds arms on both faces of the same column and suits open-floor layouts with forklift access on two sides. Pick by warehouse layout and forklift flow, not by preference.

How much weight can a cantilever arm hold?

Arm capacity varies by class. A 200kg per arm class suits PVC pipe and light timber. A 500kg per arm class fits steel bar and heavier lumber. Heavy industrial cantilever systems can exceed 1000kg per arm. Rated capacity drops as arm length increases because of deflection, so always check the rating at your actual arm length.

Is cantilever racking better than pallet racking?

Not better, just different. Pallet racking handles palletised uniform stock within beam span. Cantilever racking handles long or irregular stock that extends past beam length. A warehouse with mixed inventory usually needs both. Using pallet racks for long stock damages beams. Using cantilever for palletised stock wastes vertical space.

What safety checks does cantilever racking need?

Check column anchoring to the slab, base plate condition, arm locking pins, and plumb alignment. Inspect for forklift impact at column base and arm tips. Verify loads sit evenly across arms with heavier stock on lower levels. Scheduled inspection aligned with SEMA guidance catches early damage before arm failure.