Pallet Support Bars: When Pallets Need Beam Support

Pallet support bars for racking are the fix for a pallet that will not safely span its two load beams, whether damaged, undersized or a plastic pallet that sags under load. SEMA caps a loaded beam’s deflection at 1/200 of its span, but a failing pallet drops through regardless. This blog walks you through when a pallet needs extra support, starting with the pallet racking systems they fit.

What are pallet support bars and what do they do?

Pallet support bars are steel bars that run front to back across the two load beams of a bay, giving a pallet a bearing surface where it would otherwise span open air. They sit under the pallet and carry its load onto the beams, so a pallet that does not reach or rest cleanly on both beams is held instead of dropping between them.

The failure they prevent is the drop through. In standard pallet racking a forklift driver has to place each pallet precisely across the front and rear beams, and a pallet placed short, split or warped can fall through the gap between them. Two or three support bars per position turn that open gap into a supported surface and give the driver a wider margin of error on a high level placement.

They mount on the step of a step beam and span the bay depth. A typical support bar runs 838mm or 1219mm to suit common bay depths, rated around 650kg to 750kg uniformly distributed, and sits flush in the beam step so the pallet lands on the bars and the beams together. The bars are part of how rack components work together, not a bolt on afterthought.

Fit support bars wherever the pallet cannot be trusted to span the beams on its own. They are the difference between a supported load and a load waiting to fall.

Do pallet support bars increase my racking’s load capacity?

No, and this is the single most common misconception about them. Support bars redistribute a pallet’s load onto the beams and stop the pallet failing between them, but they do not raise the safe working load of the beams or the uprights. Adding more bars never lets a bay carry more than its rated beam and bay loads.

The distinction matters for safety. A bay rated for a given load is rated on its beams and frame, and a support bar changes how the pallet sits on those beams, not what those beams can hold. A team that treats support bars as a capacity upgrade overloads a bay that still has its original limit, which is why the beam and bay load limits on the load notice stay unchanged when bars are added.

What the bars do change is the load path. They spread a concentrated point load more evenly across the beam and reduce local beam twist, which protects the beam without adding to its rating. SEMA’s deflection tolerances treat that beam movement as a separate matter from what the beam can safely hold. The support bar solves a pallet problem, not a capacity problem.

Never buy support bars to add capacity, because they do not. They make the rated capacity usable by a pallet that could not otherwise reach it safely.

When does a pallet actually need support bars?

When the pallet cannot span both beams reliably on its own, which comes down to four cases: damaged pallets, undersized pallets, plastic pallets that deflect, and pallets stored in the wrong orientation. Each puts the load somewhere the beams do not catch it.

A damaged pallet is the clearest case. A split board, a broken stringer or a warped deck can give way between the beams even when the pallet is the right size, so the bars carry the load the failing pallet no longer can, and storing on a broken pallet is exactly the kind of unsafe load the MOM circular on the safe use of storage racks puts on the occupier to control. A rack inspection that flags damaged pallets in storage usually produces a support bar retrofit alongside the pallet replacement.

The undersized pallet is the next. A pallet shorter than the bay depth does not reach both beams, so it rests on one and overhangs into the gap, and an international Euro pallet at 1200 by 800mm placed into beams pitched for a 1200 by 1000mm pallet is the classic mismatch. Support bars close the gap the small pallet leaves.

Fit bars for the pallet you actually store, not the pallet the rack was designed around. The rack is rated for a standard pallet; the bars handle everything that is not one.

Why do plastic pallets need extra support more than timber?

Because plastic pallets deflect and creep under sustained load in a way timber does not, so a plastic pallet sound enough to lift can still sag dangerously once it sits loaded on a rack for weeks. The material flexes, and under a constant heavy load it keeps flexing.

The mechanism is creep. A loaded plastic pallet supported only at its edges sags at the centre, and over time under load, made worse by warehouse heat, the supported edges migrate inward toward each other. If those edges creep far enough in, the pallet slips off the beams and falls. This is a slow failure that a visual check on day one does not catch.

Deflection follows simple beam behaviour. A plastic pallet’s bottom rails are thin and supported only at their ends, and deflection rises with load and span and falls with the material’s stiffness, so a polyethylene or polypropylene pallet with a low stiffness deflects far more than a timber one at the same load. Support bars cut the unsupported span, which is the direct lever on that deflection.

Support every racked plastic pallet carrying a sustained heavy load, because creep is a question of when, not if. Timber warns you by cracking; plastic sags quietly until it slips.

How does pallet size and orientation decide it?

The pallet only bears safely when its stiff members land across both beams, so size and orientation together decide whether it spans or slips. Get either wrong and the pallet loads the gap instead of the steel.

Orientation is the hidden trap. A stringer pallet, the two way type, only bears properly when its stringers run front to back across the beams, and the same pallet turned ninety degrees rests on its weak deck boards and can collapse into the bay. A block pallet, the four way type, bears in both directions but still needs to reach both beams. Storing a stringer pallet the wrong way is a support bar case even when the pallet is sound and the right size.

Size sets the span. A rack set for a 1200 by 1000mm pallet expects that footprint to reach both beams, so a smaller or non standard pallet leaves a gap, and matching the pallet to the bay depth and beam pitch is what decides whether bars are needed at all. The pallet’s supported dimension, not its overall size, is the number that matters.

Check the pallet’s bearing direction before its dimensions. A correctly sized pallet stored the wrong way is as unsupported as one that is too small.

Support bars or wire decking: which should you use?

Support bars for a pallet problem, wire decking for an everything else problem, because the two solve different things. Support bars are two or three discrete lines under the pallet’s bearers; wire decking is a full area mesh deck across the whole beam level.

Support bars win when the load is a pallet that just needs a reliable bearing surface. They are cheaper than a full deck, quick to drop into the beam step, and targeted at the specific bays holding problem pallets. A run of standard pallets with a few undersized or plastic ones needs bars only in the bays that have them.

Wire decking wins when the load is not a clean pallet at all. Hand stacked cartons, loose items, small boxes, or a picking level worked by people need the continuous surface a deck gives, and the role of wire decking on beam levels covers where full coverage earns its cost. A deck also helps with sprinkler water flow and stops small items falling through.

Choose bars for pallets and decking for everything else. Paying for a full deck to support a pallet that two bars would hold is spending on coverage you do not need.

How many support bars per pallet, and how are they fitted?

Two per pallet position as standard, under the pallet’s two bearer lines, and three for a heavy or a plastic pallet that needs the extra span reduction. The bars sit in the step of the beam and are positioned to land under where the pallet actually bears, not spaced evenly for their own sake.

Placement follows the pallet. Each bar goes under a stringer or bearer line so the load path runs pallet to bar to beam, and a bar sitting where the pallet has no bearer does nothing. For a plastic pallet prone to centre sag, a third bar down the middle shortens the unsupported span where the deflection is worst.

The fit has to match the beam. Support bars are cut to the bay depth and profiled for the beam step, so an 838mm or 1219mm bar suits its matching beam, and a bar that does not seat properly in the step is not carrying the load it appears to. The bar is only working when it is seated and under a bearer.

Position the bars under the load, not across the bay at even gaps. A support bar in the wrong place is decoration.

Support the pallet, not the misconception

Pallet support bars fix the pallet, not the rack. They give a damaged, undersized, plastic or wrongly oriented pallet a reliable bearing onto the beams and stop the drop through that a failing pallet invites, without changing the beam and bay ratings. The pallet’s span, orientation and material decide whether bars are needed, and a plastic pallet under sustained load needs them before it starts to sag.

Send us the pallet types and sizes you store against your bay depths, and we will tell you which positions need support bars and how many. Request a pallet compatibility check.

Frequently asked questions

Do pallet support bars increase the weight capacity of a rack?

No. Support bars distribute a pallet’s load onto the beams and stop the pallet failing between them, but they do not raise the safe working load of the beams or uprights. Adding more bars never lets a bay exceed its rated beam and bay loads, which stay fixed on the load notice regardless of how many bars are fitted.

How many support bars do I need per pallet?

Two as standard, positioned under the pallet’s two bearer lines, and three for heavy or plastic pallets that sag at the centre. The bars must sit under where the pallet actually bears, not at even spacing, because a bar placed where the pallet has no bearer carries nothing. A typical bar spans 838mm or 1219mm to suit the bay depth.

Can I store a pallet the wrong way round if I fit support bars?

Support bars let you store an undersized or non standard pallet safely, and they are the correct fix for a stringer pallet that cannot be turned to run its stringers across the beams. A sound block pallet bears in both directions, but a two way stringer pallet stored across its weak boards needs bars to prevent collapse into the bay.

Do all plastic pallets need support bars on racking?

Every plastic pallet carrying a sustained heavy load on a rack should be supported, because plastic creeps and deflects under constant load in a way timber does not. A plastic pallet supported only at its edges can sag until it slips off the beams, so cutting its unsupported span with two or three bars is the standard control.

What is the difference between a support bar and pallet decking?

A support bar is a discrete steel bar under a pallet’s bearer line, fitted two or three to a position for problem pallets. Pallet or wire decking is a full area surface across the whole beam level, used for hand stacked cartons, loose items and picking. Bars solve a pallet problem; decking solves a loose load problem.