This i

I don't know the answer to that question but I do have something to add. Wouldn't the species of wood make a difference? Since different woods have different cellular construction and physical properties, wouldn't their tresholds of cellular crush (compression set) be different? That is how I see it. And if that is the case, since they can't agree on the JANKA scale about hardness with different species, how could they (U.S. Dept. of Forestry, NOFMA, NWFA, etc.) establish thresholds of compression set. I look at it this way. If I see a floor that is cupped, I'll ask how long. If it's been that way for a season or two, I figure that if it shrinks, there will be gaps from compression set. If caught quickly and it isn't severe, it's possible it's may go back down just fine. I've seen both happen but never seen a badly cupped floor flatten out completely after it was dried.