Plugs, plates and companion stringers: reading a repair

01 Three repairs

Plug

Between 6 and 24 inches long, nailed beside the broken board. Common on top decks.

Plate

A metal plate over a cracked stringer or block, with teeth that bite into the wood.

Companion stringer

A new timber alongside a split one. Adds strength where the original failed.

02 How to judge each

A plug on a deck board is cosmetic for most loads. A plate over a stringer deserves a second look under a heavy load, because the metal fixes the crack but the wood around it has already failed once. A companion stringer is usually more robust than a plate.

03 Limits

Millwood's guide says grade B pallets may have repaired stringers or plugs greater than 1 and a quarter inches. Count the repairs on a sample pallet. If most pallets in the stack have two or more, look at the grade C page.

04 A repair checklist

1. Count the plugs and plates on a sample of ten pallets.
2. Check that plates are flush, with no sharp teeth proud.
3. Check that plugs are nailed at both ends.
4. Flex the pallet by hand. A pallet that gives under a hand will give under a load.

05 Questions to ask about a repair

• Is the part on the load-bearing side or on the top deck?
• Do any nail ends stick out where a hand or a case could catch?
• Is the repair at a corner, which takes the most knocks?
• Has the pallet been re-inspected after the repair?

06 Alternatives

Some repairers replace a damaged stringer entirely instead of plating it. That makes a stronger pallet but costs more.

07 Plugs and plates in the grading text

In Millwood's grading, the premium band allows no stringer repairs, the A band allows minor stringer repairs that are solid or plated, and the B band allows repaired stringers or plugs larger than 1.25 inches with deckboard spacing of 4 inches or more. A plated stringer is therefore acceptable in two of the three bands, and what changes between them is how many repairs and how large.

08 Out of square

Millwood's bands each allow a pallet up to 1 inch out of square, and its premium band also requires at least 60% bright wood. A repaired pallet that is badly out of square will not seat evenly on a rack beam, which is a separate test from whether the repair holds.