Identify & Quality Check · Inspection
Plywood Defects and How to Identify Them
Most plywood defects trace back to manufacturing or storage problems, and nearly all of them are visible on a careful inspection before you buy — if you know what to look for.
Five Common Plywood Defects
Warping & Bending
Sight down the length of the sheet on a flat surface — any visible curve or twist usually means poor storage or an unbalanced layer construction.
Delamination
Layers separating at the edge, even slightly, signal a weak adhesive bond and will only get worse with use or moisture exposure.
Core Gaps & Voids
Check a cut edge for hollow spots or gaps between core strips — these weaken the sheet's structural integrity, especially near where hardware will be fixed.
Surface Cracks & Bubbling
Cracks, splits or raised bubbles in the face veneer usually point to poor pressing during manufacturing or moisture trapped beneath the surface.
Uneven Thickness
Run a hand or straightedge across the sheet — noticeable high or low spots indicate inconsistent manufacturing and will cause problems under laminate.
When to Reject a Sheet Outright
Any visible delamination, significant core voids, or warping severe enough to see without a straightedge are reasons to reject a sheet on the spot rather than hoping it won't matter once installed — these defects don't improve with use, they get worse.
Preventing Defects After Purchase
Proper storage — flat, dry, off the ground — prevents many of these defects from developing even in a good-quality sheet. See our how to check plywood quality guide for the broader buying checklist, and our calibrated vs normal plywood guide for more on thickness consistency specifically.
Frequently Asked Questions
What are the most common plywood defects?
Warping, delamination, core gaps or voids, surface cracks or bubbling, and uneven thickness are the most common defects to check for before buying.
What causes plywood to delaminate?
A weak or improperly cured adhesive bond during manufacturing, often made worse by moisture exposure after purchase, causes the layers to start separating.
How do I check for core gaps in plywood?
Look at a cut edge of the sheet — hollow spots or visible gaps between the core strips indicate voids that weaken the sheet's structural integrity.
Should I reject a plywood sheet with minor surface marks?
Minor cosmetic marks on a lower face grade may be acceptable depending on the application, but any delamination, significant core voids, or visible warping are reasons to reject the sheet.
Can proper storage prevent plywood defects?
Yes — storing sheets flat, dry and off the ground prevents much of the warping and moisture-related damage that can develop even in a good-quality sheet after purchase.
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