I just purchased 30 sheets of new 1/2 inch spruce plywood for use as subflooring. As I worked, 2 of the first 8 sheets spontaneously delaminated as I was cutting them. Not just a little at the edges, but in sheets of several square feet. The adhesive that is supposed to bond the plies is visible (dark colour) but it appears to have come unstuck. Has anyone encountered this behaviour before?

  • 1
    I would return the entire batch and go elsewhere for more. Too risky otherwise ...
    – brhans
    Dec 23, 2019 at 15:55
  • Never experienced it but it sounds defective. You should return it unless you actually plan to glue it back together.
    – MonkeyZeus
    Dec 23, 2019 at 16:14
  • I plan to return the whole lot, but I am also wondering if it makes much of a difference in my application. The plywood will be sandwiched between the subfloor and my new hardwood flooring. There will be screws holding the plywood to the subfloor and cleats holding all three layers together. THe fasteners may well be stronger than the glue between the plies, even if the glue actually sticks!
    – jLegris
    Dec 23, 2019 at 19:10

1 Answer 1


It sounds like the mill’s blow detector was not functioning. Or a bad batch of glue, , plugged nozzle several possibilities, take it all back. I used to work in a plywood mill and with 2 sheets bad that unit probably will all have the same issue. I would take the cut sheets back. The mill randomly pulls sheets and chizzles chunks and those chunks only a couple inches square have to stick together. So take it back and get some from a different unit.

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