Forty-plus nail pops have gradually appeared in 3 year old Congoleum VCT square tile "linoleum" kitchen floor. Pattern of pops coincides with duct work in basement. Is it possible pooled condensation on top of ducts affected subfloor of kitchen floor causing pops? Some of ductwork is insulated, some is not. Duct work hangs about five inches below subfloor below kitchen floor. Unrelated to pops, we set up dehumidifier in basement several months ago, so no longer experience dripping condensation.