Lately I've noticed a problem in my living room floor in that the wood
is buckling or crowning a bit with gaps between the boards directly
above where there is an HVAC duct running underneath between the floor
joists( about 10 feet length total). I think it has gotten worse this
past year because recently I finished my basement and closed the
ceiling with sheetrock, so I'm guessing all the heat from the duct is
concentrated upward towards the floor, although I thought wood shrinks
when its warm and dry instead of expand. Is there an easy fix for
this? Can it be hammered down with a 2X4 and hammer?