Plywood bows in the middle of a 12-foot sheet surprised me last Thursday

I stacked some 3/4 inch birch flat in the garage for 3 days before cutting cabinet doors, and the middle sheets had a 1/4 inch hump from just the weight of the pile. Has anyone else had their lumber supplier's storage cause weird warping right out of the stack?

2 comments

2 Comments

parkerk563d ago

The 1/4 inch hump is probably from the veneer layers inside the sheet, not just the weight. Those inner plies can have uneven moisture content from the factory, and 3 days flat isn't nearly enough time for that to even out. Your supplier's storage might get the blame, but that birch could've been bowed before it ever hit their racks.

matthewf405d ago

You're surprised a 1/4 inch hump happened from stacking 3/4 inch plywood flat? That's pretty normal for birch, especially if it sat in the supplier's warehouse a while before you got it. Throw some weight on it and see if it flattens out before you worry too much.