Block vs Stringer Pallets: What Your Dock and Racking Expect

Block vs stringer pallets comes down to what carries the deck: nine solid wood blocks in a 3x3 pattern, so forks and pallet jacks enter from all four sides, or three boards running the long way, so entry is from two sides. We stock the 48x40 block pallet; heat treated comes in either build.

Block vs stringer pallets at a glance

Item	Block pallet	Stringer pallet
Support under the deck	Nine solid wood blocks, three rows of three, between the top and bottom deck boards	Three boards (stringers) running the long way of the pallet
Forklift and pallet jack entry	True 4-way entry from any side, without structural compromise	2-way entry; notched stringers admit forks from the side, not a pallet jack
48x40 pallet weight	33-48 lbs	Varies by lumber and build
48x40 load	About 2,500 lbs dynamic safe working limit; 2,500-4,600 lbs static	Depends on the lumber; less even weight distribution than block
Trailer count (48x40)	Two side by side in a 53-foot trailer, roughly 26 in one layer	Same footprint, same count
Racking and automation	The build automated racking and high-bay systems are designed around	Common on domestic freight; orientation matters at the conveyor
Export (ISPM-15)	Heat treated available: 56C at the core, 30 continuous minutes, stamped IPPC	Heat treated available in stringer configuration too
Inbound surplus	Bought in reusable condition; free pickup from 30	Bought in reusable condition; broken stock removed free from 50

Block vs Stringer Pallets: What Sits Under the Deck

Turn a pallet on its side and the difference is obvious. A stringer pallet is the older design: three boards, called stringers, run the length of the pallet, and the top and bottom deck boards are nailed across them. The stringers are what the forks slide between, which is why the pallet has a front and a back. A block pallet does away with the long boards. The deck sits on nine solid wood blocks, one at each corner, one at the middle of each edge and one in the center, tied together by the bottom deck boards. Nothing continuous runs along the sides, so there is nothing to block the forks from any direction.

The 48x40 standard block pallets we stock at the yard on East 78th Street are built that way: nine blocks in a 3x3 pattern, true 4-way entry, and a more rigid platform than three stringers give, because the blocks spread the weight across the deck instead of concentrating it on three lines.

Both builds share the same footprint, and the figures in the standard pallet dimensions chart apply to either construction. What changes is not the size. It is what happens when the pallet meets a pallet jack, a racking beam, a conveyor sensor or a customs inspector.

At the Dock: How the Forks Get In

The dock is where the stringer vs block pallets question usually gets settled, because the dock is where a pallet either moves on the first try or does not.

True 4-Way Entry on a Block Pallet

Nine blocks leave clearance on all four sides of the pallet. A forklift can take it from the long side or the short side, and a pallet jack can do the same, because the bottom deck boards are spaced to let the jack wheels drop through and come up under the load. The operator does not have to look at the pallet before approaching it.

That matters most where there is no room to maneuver. The food plants in Vernon run around the clock in buildings that were never laid out for a forklift to swing a load through a half turn, and a pallet that accepts the forks from whichever side faces the aisle removes a move from every pick.

2-Way and Notched Stringers With a Pallet Jack

A plain stringer pallet is 2-way: the forks enter along the stringers, from the front or the back. Many stringer pallets are notched, with a section cut out of each outer stringer so forklift forks can enter from the side as well. That is often called partial 4-way entry, and the word partial is doing real work. The notch is high enough for forks, but the bottom boards and the stringer are still in the way of a pallet jack, whose wheels have to ride on the floor.

On a cross-dock floor in Carson or Compton, where a receiving crew may run pallet jacks for most of its moves, that single limitation decides more than any load rating does. If the jacks do the work and the inbound freight arrives on stringers, every pallet has to be lined up front-on before it moves. We make pallet deliveries to Carson and Compton cross-docks several times a week, and the first question on a new account is rarely the load. It is who moves the pallet.

Three questions settle the dock side of the decision:

• Who moves the pallet most often? Pallet jacks need 4-way entry to work from the side; a counterbalanced forklift can take a notched stringer from the side.
• Which side faces the aisle? If the answer is “it depends on who stacked it”, block construction removes the problem.
• Does the pallet come back? A closed loop can standardize on one build; an open loop inherits whatever arrives.

In the Racking and on the Conveyor

Once a pallet leaves the dock it meets the racking, and in more and more Southern California buildings it meets a conveyor or a shuttle before any person touches it again.

The Load Figures for the 48x40 Block Pallet

The block pallet we stock weighs 33 to 48 lbs. Its safe working limit while it is being moved is around 2,500 lbs, and it holds 2,500 up to 4,600 lbs sitting still, depending on the build. In a 53-foot trailer it goes two side by side, roughly 26 to a layer, the same count for either construction because the footprint is identical. We do not print load figures for stringer pallets: the rating depends on the lumber and on the condition of the three boards. What anyone who has racked both builds knows is that nine support points spread the load more evenly than three, which is why the block pallet is the one we put in racking without a second thought. The difference between static, dynamic and racked load is explained in the three load numbers that matter.

Why Automated Picking Lines Ask for Block

High-bay racking and automated handling systems are designed around block construction. A block pallet presents the same profile from every side, and a conveyor sensor, a pallet shuttle or an automatic guided vehicle is built to expect a profile, not to adapt to one. A stringer pallet presented the wrong way round is a reject, and a reject on an automated line stops more than one pallet.

That is why the spec-built distribution centers along the I-10 corridor in Fontana and Rancho Cucamonga, the newest and largest in the country, write tight dimensional tolerances into their pallet requirements for automated conveyor and robotic picking. Those systems need pallets that are consistent and structurally sound, order after order, and a pallet supplier for Inland Empire distribution centers has to deliver the same block pallet in October that it delivered in March. The lot, not the single pallet, is what the line sees; pallets for automated warehouses covers how to specify it.

On the Export Lane: Heat Treated in Either Configuration

The export dock asks a different question, and it has nothing to do with blocks or stringers. Heat treatment under ISPM-15 is a process applied to the wood: the core of the lumber is brought to 56C (132.8F) and held there for at least 30 continuous minutes, then the pallet is stamped with the IPPC mark, the US country code, the facility code and the HT treatment code. Because it is a process and not a construction, we supply heat treated ISPM-15 pallets in both block and stringer configurations, in every standard and custom size.

What the inspector at the destination port checks is the stamp, legible on two opposite sides. Two things undo a compliant pallet: a worn or painted-over mark, and the dunnage mistake, where a stamped pallet loaded with untreated blocking or bracing lumber flags the whole shipment, because every piece of solid wood packaging in the container has to be treated. Plywood is exempt. Nothing about block vs stringer pallets changes that rule.

What to Do With the Stringers That Arrive Inbound

A warehouse that standardizes on block pallets does not stop receiving stringer pallets. Inbound freight arrives on whatever the shipper used, and within a few weeks there is a stack of stringers behind the building that the outbound trucks cannot use and the racking does not want.

That stack has a route. We buy block and stringer pallets alike when they are in reusable condition, paid on the spot, and the pickup is free from 30 pallets; below that, a small fee that depends on where you are. Broken stock, the pallets with cracked stringers or missing boards, is removed free from 50, and each leg is quoted on its own. The crew loads; nothing has to be sorted first. The block pallet vs stringer pallet choice for the outbound order is easier to make once there is somewhere for the inbound ones to go, and we buy the stringer pallets that pile up at the receiving door, on trucks that are already in Vernon and Commerce several days a week. From 100 pallets, the delivery of the outbound order is free.

Frequently Asked Questions

Can a pallet jack enter a stringer pallet from the side?

Usually not. A stringer pallet is built for 2-way entry along the stringers. Notched stringers let forklift forks in from the side, but the bottom boards and the stringer itself still block the wheels of a pallet jack. A block pallet gives a pallet jack true 4-way entry.

How much weight does a 48x40 block pallet hold?

The 48x40 block pallets we stock are rated around 2,500 lbs while being moved and 2,500 up to 4,600 lbs static, depending on the build. Each pallet weighs 33 to 48 lbs.

Do I need block pallets for an automated warehouse?

Automated racking and high-bay systems are designed around block construction, and the automated fulfillment buildings in the Inland Empire ask for consistent, structurally sound pallets with tight dimensional tolerances. The nine blocks present the same profile from every side, which is what a conveyor sensor or a shuttle expects.

Can stringer pallets be heat treated for export?

Yes. ISPM-15 heat treatment is a process applied to the wood, not a construction style, so heat treated pallets are available in both block and stringer configurations. What customs checks is the IPPC stamp, legible on two opposite sides.