I mean, we can think of "dampness" as the over all mechanic that could apply to a bunch of things;
particularly if at a very early stage where many of your buildings resources will be made of wood/grass
Damp things could give a negative multiplier to everything around it, damp wood can slowly enter a "Rotting" stage; which would make wooden structures more temporary if not planned around. Cobblestone and Bricks can end up exposed to too much moisture and start growing Moss or Roots.
In the case of Cellars, damp/decaying blocks can effect the preservation multiplier. Or in particularly unkept cellars, become infested with mold and cause stored foods to rot faster.
Which then opens the game up to repair/reservation mechanics like Treating Wood with dyes/lacquers to prevent rotting;
Or Salting/Scrubbing stones to remove moss and slow its growth.
Or even later stage materials like concretes that will resist moisture completely.
Edit:
And thats not even to mention how is could be used in Health/Temperature mechanics,
Like being more prone to getting sick, or warming yourself being less efficient.