Reward for lost Kraken!
Join Date: Apr 2006
Thanked 141 Times in 138 Posts
Rep Power: 11
Bob, if those tricks don't lift it clear, you can take a wood toggle on a bit of line (like you'd see buttoning a classic stadium jacket), push the toggle through the hole, and then put your back into lifting on that line.
It almost always is a problem of the wood getting damp and expanding, and if you sand it down a little magically the opposite happens and the board never stays put again.
Floor boards really need to be sealed on all six sides (top, bottom, and the edges) or they'll find a way to change size on you. Or, you install them a little loose and use slides or pulls that can secure them down.