Presswood (wood-composite) pallet blocks

What presswood blocks are

Presswood or wood-composite blocks are the spacers in a block pallet, molded from wood fiber and resin rather than cut from solid lumber. They are common on export block pallets, paired with a solid-wood deck and stringerboards. Don't confuse them with one-piece presswood pallets, which are molded as a single nestable unit.

Uniform Standard requirements

The Uniform Standard for Wood Pallets (2012, Section 5.3) sets physical requirements and tests for composite blocks:

Tolerances

In plain terms, the tests check that a block does not swell badly when wet, survives side loading from forklift tines, accepts nails without excessive driving force, and still holds those nails.

Why use composite blocks

• ISPM 15 exempt. Composite blocks are processed wood, so the blocks themselves need no heat treatment. Solid-wood deckboards and stringerboards on the same pallet still do.
• Consistent size and density. A molded block has no knots, splits or wane.

Composite vs solid-wood blocks

Things to check

• Nail type and length. Block pallets typically use about 3 in annular nails through the stringerboard into the block. Confirm the block supplier's nail recommendations and the pallet's per-block nail count: the Uniform Standard minimum is 3 at a corner block and 2 at an interior block.
• Moisture exposure. Specify composite blocks that meet the soak test if pallets will sit outdoors or in wet environments.
• Supplier data. Ask for test results against each property in the table above.

What to ask a composite block supplier

1. Density, and how it is controlled batch to batch.
2. Results for the 24-hour soak test: weight gain and swell in each direction.
3. Side tine compression results.
4. Nail insertion and withdrawal results, with the nail used in the test.
5. Block sizes available and their tolerances.
6. The recommended nail type and length for their blocks.

Compare the answers against the Uniform Standard values in the table above. If a supplier cannot provide test data, treat that as a risk for reusable or export pallets, where blocks take repeated fork impacts and may get wet.

How presswood blocks show up on a spec

The block line on a PDS-style spec lists the block type (Lumber, Laminated panel, or Wood composite), count, width, height and length, for example "Wood composite; 9; 3.5 x 3.5 x 5.5". The fastener section lists the top-deck-to-block and bottom-deck-to-block nails separately. See stringer vs block pallets.

How palletdesign.ai handles block material

palletdesign.ai draws block pallets with 9 blocks in a 3 x 3 layout and sizes them from your inputs, as in the 48 x 40 block and EUR / EPAL 1 templates. Its weight and cost factors are for the solid-wood species you select, so they do not yet distinguish composite blocks from lumber blocks. If you plan to use composite blocks, note it on the RFQ; the geometry, parts list and nail count still apply. Any capacity figure in the app is indicative only.