Pallet repair: methods, standards and when a pallet is not worth fixing

Pallet repair keeps hundreds of millions of pallets in service every year. Virginia Tech and USDA Forest Service research estimated that about 280 million US pallets were repaired or remanufactured in 2021. Done well, a repair gives a pallet many more trips for a fraction of the price of a new one. Done badly, it produces a pallet that fails under load, jams automation or gets refused at a retailer's dock.

#Common pallet damage

#Repair methods

The Uniform Standard for Wood Pallets and ISO 18613 (Repair of flat wooden pallets) describe accepted repair practices. The common methods:

#Deckboard replacement

The broken board is removed, nails are pulled or cut flush, and a new or recycled board of equal or greater size is nailed in. Good practice:

• Use a board at least as thick and wide as the original.
• Nail into sound wood, not the old nail holes.
• Use the same nail count per joint as the original design, at least the minimums in the Uniform Standard (2 per joint for boards up to 5-1/4 in wide, 3 for wider). See pallet nails and fasteners.
• The Uniform Standard restricts low-density species (classes 7, 13 and 14) to interior deckboards in repairs.

A doubled (or "sistered") board, where a new board is nailed beside a broken one without removing it, is a quick repair that some grades allow and many buyers do not.

#Companion stringer

A companion stringer is a board nailed alongside a cracked or broken stringer, full length or partial, to carry the load across the damage. It is the most common stringer repair. It adds weight and can narrow the fork opening. Most vendors grade a pallet with a companion stringer as Grade B.

#Plugs and C-blocks

A plug is a short block nailed against a stringer to reinforce a local crack, often at a notch. A C-block is a block shaped to fit around the damaged section. Both are listed repair components in the Uniform Standard.

#Metal connector plates

Toothed steel plates pressed into both sides of a cracked stringer hold it together. They are fast and cheap, but some buyers ban them because they can snag product and handling equipment, and Walmart does not allow them on stringer pallets.

#Block replacement (block pallets)

Damaged blocks are cut out and replaced, and the stringerboard and deckboards renailed. On pooled pallets, only the pooler may do this; Costco rejects pooled pallets with unauthorized repairs.

#How much strength does a repair restore?

Less than new. The durability simulation in the Pallet Design System (PDS) uses published assumptions about repairs:

These are modeling assumptions, not rules. But they explain why a heavily repaired pallet does not last as long as a new one, and why wide stringers and blocks (more wood for new nails) make pallets more repairable.

#When is a pallet not worth repairing?

Dismantle or recycle a pallet instead of repairing it when:

• More than one stringer or several blocks are broken
• The wood is rotten, moldy or soft
• The pallet is contaminated with chemicals, oil or food residue
• It is a pooled pallet (CHEP, PECO, iGPS): return it to the pooler
• The repair would cost more than a Grade B replacement
• The pallet goes to a customer that does not accept repairs

See pallet recycling.

#Export: repaired pallets must be re-treated

Under ISPM 15, a pallet with any new or replaced wood must be re-treated as a whole and re-marked, and previous marks must be obliterated. A pallet with a new board and the old HT stamp is not compliant, and can be refused at a border. Intact HT pallets can be reused without re-treatment. See heat-treated pallets.

#Repair marks

The Uniform Standard recommends marking repaired pallets with:

• Class of repair
• Repairer identification
• Date of repair
• Owner

It recommends a mark at least 2 in (51 mm) high with 1 in (25 mm) letters. Marks let owners of closed-loop pallet fleets track repair counts and hold repairers accountable.

#Running an in-house repair program

For a plant or DC with its own pallet fleet:

1. Sort at receiving. Separate good, repairable and scrap pallets. See pallet inspection.
2. Stock standard parts. Pre-cut deckboards and companion stringers to your design's dimensions.
3. Use the right nails. Threaded nails of the original gauge, not whatever is in the nail gun. A pneumatic tool loaded with thin collated nails produces a weaker repair.
4. Set limits. Maximum number of repairs per pallet; no plates if customers reject them.
5. Mark repairs so you can count them.
6. Compare with outsourcing. Many recyclers offer repair and sort services on site or at their yard.

Remember the safety side: repair stations involve nail guns, saws and heavy lifting. Follow your site's safety procedures.

#Repair specs for closed-loop fleets

If a third party repairs your own pallets, write a repair spec: which methods are allowed (board replacement only, or companion stringers and plates too), replacement board dimensions and grade, nail type and count, maximum repairs per pallet, repair marking, and when a pallet is scrapped instead. Inspect repaired pallets on return as you would new ones.

#Repairing plastic and metal pallets

Plastic pallets are generally not repaired; broken plastic pallets are ground and the resin reused. Some structural foam and rotomolded pallets can be welded, but repaired plastic pallets rarely keep their original ratings. Metal pallets can be re-welded or straightened by a fabricator, and galvanized pallets may need the coating touched up after repair.

#Repair or replace: a quick cost check

Compare the cost of a repair with a Grade B replacement:

For a closed-loop fleet of custom pallets, repair is usually worthwhile because replacement pallets are custom-built and expensive. For standard 48 × 40 in stringer pallets, the break-even is lower because Grade B replacements are cheap.

#Designing pallets that repair well

If you buy new pallets that will be repaired over their life:

• Wider stringers or blocks (1-1/2 in or more) leave room for new nails beside old holes.
• Standard board sizes make replacement parts easy.
• Wider lead boards resist fork damage, the most common failure.
• Chamfered bottom lead boards reduce pallet jack damage.

You can set these in the designer; the GMA 48 × 40 template is a common starting point, and pallet grades explains how repairs affect a pallet's grade.