Combi core versus
poplar core.
The core of a plywood panel is the stack of veneers under the face film. “Combi” means that stack mixes species — eucalyptus, pine and fir — instead of using one cheap species throughout. It is the difference between a panel that holds a screw in its third pour and one that does not.
Two words on a quotation, two different panels
A quotation that says “plywood core” or “mixed core” has told you nothing. Those words cover poplar, which is the cheap default, and they cover a declared mix of denser species. The two panels weigh differently, hold fixings differently, and do not cost the same. The only way to know which one you were quoted is to ask for the species, in writing, on the invoice.
This is why we write ours as combi core (eucalyptus + pine + fir) rather than as a single species, and why we do not write “pure eucalyptus core”: our panels are mixed by construction, and claiming a single species would be a misdeclaration that a buyer could test with a knife and a light.
What the species actually changes
| Behaviour | Poplar core | Combi core, eucalyptus / pine / fir |
| Screw and tie holding | Softer, fixings pull out earlier and the hole widens | Denser veneers hold the screw through more strips |
| Thickness under pressure | Compresses more under fresh concrete, joints step | Stiffer stack, joint stays flatter for longer |
| Weight per panel | Lighter, so more panels reach the payload limit | Heavier, so fewer panels per container |
| Public price band, 18 mm | About USD 280–360 per m³ (Woodexy, 2026) | About USD 320–410 per m³ (Woodexy, 2026) |
| Where it suits | Low-rise work, short cycles, price-led tenders | Repeat pours, tall walls, work where panels are reused |
The public bands above sit roughly 12–15 % apart. On a 40HQ that is a real number, which is exactly why the cheap quote exists: it is a different panel, not a discount on the same one.
Why the gap is smaller than it looks
A panel is bought once and used many times, so the relevant figure is cost per pour, not cost per panel. Divide the panel price by the number of pours it survives, and add what you spend keeping the face usable: edge paint after every cut, washing instead of sanding, dry flat storage. A poplar-core panel at the low end of its band that gives four pours can cost more per pour than a combi panel at the top of its band that gives nine — and the second panel also leaves a better concrete face, which is the part nobody prices until the finish is rejected.
The arithmetic is in our reuse note; the loading consequence — fewer heavier panels per container — is on the specifications page.
Three things to ask for, before the deposit
The species of the core and the face veneers, in writing. The bending and bonding figures from a report with a number, not a brochure. And a cut sample from the batch you are buying — not from the showroom panel, which is always the best one in the plant.
Our own numbers are on the quality page: bonding 0.7–1.9 MPa, static bending 50/43 MPa lengthwise and 40/30 MPa crosswise on the 18 mm panel, from CMA report JC21-WT0099.