LTL freight gets handled multiple times between pickup and delivery. Each load, unload, and cross-dock transfer is a touchpoint where things can go wrong. For refrigerated freight, there is an additional layer: every time those trailer doors open, temperature is at risk. Poor packaging does not just invite physical damage - it blocks the airflow that keeps the reefer trailer working, creates hot spots that spoil product, and triggers reclassification charges that inflate the invoice.
This guide covers how to package temperature-controlled freight for LTL so it arrives intact, at temp, and without surprise charges.
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Standard LTL packaging rules apply to refrigerated freight: square the stack, wrap it tight, label everything. But reefer LTL adds three factors that make packaging more consequential than for dry shipments.
First, LTL means multiple handling events. Your pallet gets loaded at pickup, transferred at a cross-dock (often into a different trailer), and delivered to the consignee. Each transfer briefly exposes the freight to ambient temperatures. Proper insulation and packaging reduce the thermal impact of those transfers.
Second, reefer trailers rely on continuous airflow to maintain temperature. The refrigeration unit pushes cold air through T-floor channels underneath the pallet, up the sides, and over the top of the load. Packaging that blocks this airflow - solid-bottom pallets, pallets flush against walls, loads stacked above the air return line - creates warm pockets inside an otherwise cold trailer. The reefer unit is running, the set point is correct, and the product still spoils because the air cannot reach it.
Third, insulation materials add weight and dimensions that shippers often forget to include in their freight classification. An insulated pallet that was quoted as Class 70 may get reweighed at the terminal and reclassified to Class 85 because the thermal blanket and gel packs added 40 pounds and two inches of height the BOL did not declare. That reclassification charge is avoidable with accurate measurement at the time of quoting.
For a full overview of how reefer LTL works, read our Complete Guide to Reefer LTL Shipping.
Start with a standard GMA 40” x 48” pallet with four-way forklift entry. This is the universal standard for LTL and fits the carrier’s dock equipment without issues. For reefer freight specifically, the pallet must have bottom deckboards that allow the trailer’s T-floor airflow to pass underneath the load. Solid-bottom pallets or sheet-covered bases block this airflow and can cause temperature failures even when the reefer unit is set correctly.
For cross-border shipments between Canada and the U.S., use heat-treated wood pallets stamped with the ISPM-15 mark, or use plastic pallets. Untreated wood pallets can be rejected at the border, adding delay and exposure time to temperature-sensitive freight.
Learn more how Cold Chain Logistics work.
Check out our Guide on how to ship pallets with LTL freight.
Stack cartons squarely on the pallet with no overhang beyond the pallet edges. Overhang creates crush risk during forklift handling and makes the pallet unstackable, which is a problem when carriers need to optimize trailer space. Heavier cartons go on the bottom; lighter on top.
Apply stretch wrap starting at the base of the pallet. Wrap around the bottom three times to bond the film to the pallet itself, then work upward with approximately 50% overlap on each pass. At the top, wrap three times with a three-inch overlap down over the top corners. For loads over 1,500 pounds, add metal or nylon banding in addition to the stretch wrap. The goal is a single, solid, stable unit that a forklift can pick up from any side without anything shifting.
For refrigerated freight, leave the stretch wrap permeable enough to allow air circulation. Wrapping too tightly with multiple opaque layers can impede the reefer’s airflow around the product. Some shippers use vented stretch wrap or leave deliberate gaps for airflow - this is especially important for produce and other respiring products that generate heat and moisture.
Try out how our Freight class density calculator can help you navigate through the shipping space headaches.
Reefer trailers maintain temperature, but they are not perfectly insulated enclosures. Insulation thickness degrades over the life of a trailer, and door seals lose effectiveness. Adding a layer of product-level insulation provides a buffer against temperature fluctuations during cross-dock transfers, loading dock exposure, and last-mile delivery.
For carton-level protection, reflective bubble-wrap liners inside corrugated boxes are cost-effective for items in the refrigerated and protect-from-freeze range. For full-pallet protection, thermal pallet blankets (sometimes called pallet parkas) wrap the entire pallet in an insulated cover that maintains temperature during periods when the freight is off-trailer - loading docks, cross-dock staging, and last-mile delivery.
The appropriate insulation depends on the temperature band. Frozen freight (around 0°F / -18°C) benefits most from supplemental insulation because the temperature differential with the ambient environment is largest. Protect-from-freeze freight (around 55°F / 13°C) may only need a thermal blanket during winter shipping to prevent accidental freezing during transfers, which is the case for the reefer LTL for cosmetics.
In most reefer LTL shipments, the trailer’s refrigeration unit maintains the target temperature and supplemental cooling is not required. But there are situations where gel packs or dry ice provide a necessary safety margin: high-value pharmaceutical shipments that cannot tolerate any temperature excursion, shipments with extended cross-dock dwell times, or last-mile delivery windows where the product leaves the reefer environment.
Gel packs maintain temperatures around 32°F (0°C) and are appropriate for chilled products. Dry ice maintains temperatures around -109°F (-78°C) and is used for frozen freight that must stay solidly frozen through extended handling. Dry ice has specific handling requirements: it sublimates into carbon dioxide gas, so packaging cannot be airtight; it requires DOT Class 9 hazmat labeling and a weight declaration on the BOL; and carriers have quantity limits per shipment.
Important: account for the weight and dimensions of gel packs, dry ice, and insulation materials when calculating freight class and dimensions. These materials can add 20–50 pounds per pallet and one to three inches of height, which is enough to change the freight class if not declared.
A reefer trailer’s refrigeration unit is designed to maintain a set temperature, not to pull product temperature down. If you load warm product into a pre-cooled trailer, the unit will struggle to maintain the set point, and the product may not reach the target temperature during transit.
Pre-cool all product to the target shipping temperature before loading. Use a thermometer to check pulp (internal) temperature, not surface temperature. A pallet of frozen food may feel cold on the outside but still carry residual heat from recent processing if it was not stored at the correct temperature long enough.
Trailer pre-cooling is the carrier’s responsibility, but shippers should confirm it happened before loading begins. A pre-cooled trailer should be at or near the set-point temperature when it arrives at the dock. If the trailer arrives warm, loading warm product into it compounds the problem.
Reefer trailers use a forced-air system: the refrigeration unit at the front of the trailer pushes cold air through T-floor channels underneath the load, the air rises through and around the product, absorbs heat, and returns to the unit along the top of the trailer. This loop only works if the air has an unobstructed path.
When loading pallets, maintain a gap of several inches between the load and the front wall, side walls, and rear doors. Never push pallets flush against the walls - this blocks the return air path and creates warm zones. Load pallets on the T-floor rails, not directly on a flat surface that blocks airflow underneath. Do not stack above the trailer’s red line (or the equivalent air-return clearance mark), which indicates the maximum load height for proper air circulation over the top.
For multi-temperature loads (common in reefer LTL), frozen product loads first in the nose of the trailer, closest to the refrigeration unit. The carrier places a bulkhead divider to seal off the frozen zone. Chilled or protect-from-freeze product loads behind the bulkhead. Packaging must be compatible with the assigned temperature zone - frozen freight needs packaging that tolerates sub-zero without cracking, and chilled produce needs ventilated packaging that allows respiration.
Proper labeling prevents mishandling at cross-docks where dock workers are processing dozens of pallets per hour. Every piece of freight needs the shipper’s and consignee’s name, address, and phone number, plus the BOL number, freight class, and weight. For reefer freight, add temperature-specific labels:
• "KEEP FROZEN" for frozen freight (0°F / -18°C and below)
• "KEEP REFRIGERATED" for chilled freight (35°F / 2°C)
• "PROTECT FROM FREEZE" for freeze-sensitive freight (55°F / 13°C)
• "PERISHABLE - DO NOT DELAY" for all temperature-sensitive shipments
These labels tell dock workers which temperature zone the pallet belongs in during staging and transfer. Without them, a protect-from-freeze pallet can end up in a frozen staging area, or a frozen pallet can sit on an ambient dock too long.
If the shipment contains dry ice, apply a DOT Class 9 hazmat label and declare the dry ice weight on the BOL. For cross-border shipments, add CFIA or FDA product identification labels, and confirm the pallet carries an ISPM-15 stamp. If you're uncertain which label to choose, read our detailed Freight class guide.
Include the required temperature range on the Bill of Lading. This is the carrier’s operational instruction for the reefer set point. If it is missing or incorrect, the carrier may set the trailer to a default temperature that does not match the product’s requirements.
1. Select a GMA 40” x 48” pallet with four-way forklift entry and bottom deckboards that allow T-floor airflow. Use ISPM-15 heat-treated wood or plastic for cross-border use.
2. Pre-cool all product to the target shipping temperature before palletizing. Check pulp temperature, not surface temperature.
3. Stack cartons squarely on the pallet with zero overhang. Heaviest cartons on the bottom.
4. Apply stretch wrap from the base up with 50% overlap. Bond the first three wraps to the pallet. Leave airflow pathways for produce or respiring products.
5. Add metal or nylon banding for loads over 1,500 pounds.
6. Add insulation appropriate to the temperature band: thermal pallet blanket for frozen or protect-from-freeze, reflective liners for carton-level chilled protection.
7. Add supplemental cooling (gel packs or dry ice) only if needed for extended dwell times, high-value pharma, or last-mile gaps. Account for added weight and dimensions.
8. Label every piece with shipper, consignee, BOL number, and handling instructions. Add temperature labels: KEEP FROZEN, KEEP REFRIGERATED, or PROTECT FROM FREEZE.
9. Declare dry ice with DOT Class 9 hazmat label and weight on the BOL.
10. Include the required temperature range on the Bill of Lading.
11. Measure and record actual weight and dimensions including all insulation, gel packs, and thermal covers. Use these numbers for freight classification.
12. Confirm the carrier has pre-cooled the trailer to the set-point temperature before loading begins.
Not accounting for insulation weight: A thermal blanket, gel packs, and an insulated liner can add 30–50 pounds and 2–3 inches of height to a pallet. If the original quote was based on uninsulated dimensions, the carrier will reweigh and reclassify the shipment at the terminal. Reclassification charges are almost always more expensive than the rate difference would have been if declared upfront.
For a breakdown of reclassification and other accessorial charges, see our LTL Accessorial Charges Guide.
Pallet overhang: Cartons stacked beyond the pallet edge get crushed during forklift handling and make the pallet unstackable. Carriers may assess an overlength or oversize accessorial, or the product arrives damaged and triggers a claim.
Blocking airflow: Solid-bottom pallets, loads pushed against trailer walls, or stacking above the air return line all impede the reefer’s circulation pattern. The refrigeration unit is running, the set point is correct, and the product still develops warm spots because the cold air cannot reach it.
No temperature labels: Without clear "KEEP FROZEN" or "PROTECT FROM FREEZE" labels, dock workers at a cross-dock facility have no visual cue for where to stage the pallet. A protect-from-freeze pallet staged in a frozen area can freeze and damage the product. A frozen pallet left on an ambient dock during a 30-minute transfer window can begin thawing.
Shipping product that has not been pre-cooled: Loading warm product into a cold trailer forces the refrigeration unit to work beyond its design capacity. The unit maintains temperature; it does not efficiently pull temperature down. The product may never reach the target temperature during transit, especially on shorter lanes.
To expand the context on the costs, read our guide on Reefer LTL shipping cost.
Proper packaging is half the equation. The other half is working with a broker who knows refrigerated freight. Freightzy’s network of 100+ vetted reefer carriers covers U.S. and Canada–U.S. lanes across frozen, refrigerated, and protect-from-freeze temperature bands. Get a quote, get packaging advice, and get your freight moving.
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Pre-cool all product to the target frozen temperature (typically 0°F / -18°C) before palletizing. Stack cartons squarely on a GMA 40x48 pallet with bottom deckboards for airflow. Wrap with stretch film, add a thermal pallet blanket for cross-dock protection, and add dry ice or gel packs only if extended dwell times are expected. Label the pallet KEEP FROZEN, include the required temperature on the BOL, and declare the total weight including all insulation and cooling materials for accurate freight classification.
The reefer trailer maintains temperature during transit, but your freight is not on the trailer for its entire journey. During LTL cross-dock transfers, loading dock staging, and last-mile delivery, the freight is exposed to ambient conditions. Insulation - thermal pallet blankets, insulated liners, or pallet parkas - provides a buffer during those off-trailer windows. The higher the temperature differential between the product and the ambient environment, the more insulation matters. Frozen freight in summer benefits most; protect-from-freeze freight in mild weather may not need any.
Yes, but with specific requirements. Dry ice requires DOT Class 9 hazmat labeling on the package, a weight declaration on the Bill of Lading, and packaging that is not airtight (dry ice sublimates into CO₂ gas and can rupture sealed containers). Carriers have quantity limits per shipment, so confirm the maximum allowed with your broker before shipping. Dry ice is most commonly used for frozen pharmaceutical freight or high-value frozen food that cannot tolerate any temperature excursion during cross-dock transfers.
Use a standard GMA 40” x 48” pallet with four-way forklift entry and bottom deckboards that allow the trailer’s T-floor airflow to pass underneath the load. Avoid solid-bottom pallets or sheet-covered bases, which block airflow and can cause hot spots. For cross-border Canada–U.S. shipments, use heat-treated wood with an ISPM-15 stamp, or use plastic pallets.
Measure and declare the actual weight and dimensions of the palletized, insulated shipment - including thermal blankets, gel packs, dry ice, and insulated liners. Many shippers quote based on the product weight alone and get reclassified at the terminal when the carrier’s scale shows a different number. Use a freight class and density calculator to confirm the correct NMFC class with the insulated dimensions, and put those numbers on the BOL.
Yes. When you book a reefer LTL shipment through Freightzy, our team can advise on packaging requirements for your specific product, temperature band, and lane. We help shippers avoid common mistakes - like underdeclaring weight, blocking airflow, or missing temperature labels - that lead to damage, spoilage, and accessorial charges. Our goal is to get your freight quoted accurately and packaged correctly before it leaves the dock.