Bare wood triggers a handling charge
Among the situations UPS lists for its Additional Handling charge is a package that is not fully encased in corrugated cardboard, per ups.com, checked 2026-07-28. A naked plywood crate meets that description, as does a drum, pail or tire without a corrugated outer. If a crate is genuinely necessary on a parcel-sized shipment, expect the accessorial and price it in before you build.
ISPM 15 is an export rule
The heat treatment stamp on pallets and crating exists for wood packaging moving between countries. For a shipment that starts and ends inside the United States it is not required, and the US plant health agency states that treatment and an ISPM 15 mark are not required when shipping from the United States to Hawaii, Puerto Rico and the US Trust Territories, per aphis.usda.gov, checked 2026-07-28. If a crate seller is charging you for a stamp on a domestic move, ask what it is for.
Crate weight is billed weight
The plywood, the frame and the fasteners all go on the scale. A stock crate rated to 500 lb is not weightless itself, so a crated shipment climbs on both axes at once, mass and volume. That is fine on a pallet, where density lowers the freight class, and expensive in a parcel network, where every cubic inch is charged.