I purchased 700 sq. ft. of Mohawk 3" X 3/8" engineered wood flooring about three years ago and it has been stored in the original boxes inside my house since then. I am just getting started with the project and have noticed that some of the strips are slightly bowed - about 1/4" over the length of a 4' board. When I first purchased the flooring I opened a couple boxes to check it, but I don't recall seeing any bowed pieces then. Will this be a problem once the strips are locked together and glued down over a concrete slab? Mohawk says if the bowing is no more than 1/4" they are okay to use. If more than 5% of the order is out of whack then I have to call the dealer. I'm afraid they'll tell me I'm SOL since I waited so long. Sure hope the boxes farther down in the stack stayed flatter! Thanks for any help.

1/4" is barely nothing. You've entered the banana board zone and will be fine.

Thanks for the reply. Also thanks to Gary, Floorguy, and Exquisite Flooring, to whom I sent private messages after panicking after not getting any replies right away. This is what I have come up with:

I am a dumb-a$$ for letting the wood sit for three years.
Very slight bowing is okay.
Since I waited so long, I probably have no recourse with the dealer to return defective pieces, but I think the bad pieces will fall within the 5% range that is considered acceptable defects.

You'll be fine.

The wood, if stored in the house, may flatten out. Bowing is a moisture imbalance so maybe you stored the wood in a Un-acclimated garage or storage room?

It was stored in my garage for a very brief period of time, but mostly has been inside my climate-controlled house. I rearranged the stack of boxes this weekend and opened a couple boxes that were farther down, so they have had a lot of weight on top of them. They were better than the boxes that had been on top, but still had some bowed pieces. I think I will be okay, as most are bowed 1/4" or less. I'll probably try flipping the worst pieces over and putting a weight on them for a while. If my flooring was prefinished on one side, unused for three years, wouldn't it absorb humidity unevenly no matter where it was stored?

I consider a bowed board, as a sideways bow. What your describing, I call banana boards. I use them if they are not real bad. Thicker flooring I cull them more, as they do promote hollow spots in gluedown.

Thanks, guys. I am now enlightened as to the difference between bowed and banana boards!