Hi Angela, welcome
You've got a wet basement or a leak. It may not have appeared damp before, but now it's covered and the moisture can't evaporate easily.
Wet floors, no place for wood products.
Tile 4 You LLC Troy, MI
KERDI Shower Specialist ... DITRA Installs ... Product-Method suitability consultation. I have NEVER made a mistake, I thought I did once...........but I was wrong! - PRODUCTS ADVERTISED WITHIN MY POST ARE NOT ENDORSED BY ME!