Originally posted by Palladin888:

it is a two story building aprox 5x8 footprint. It has support beams down the center every 3 tiles. It seems only the ground floor is taking damage. I have a proper roof

sounds like a burst water pipe, or flood damage due to global warmings.

(are you near an ocean tide?)

I thought (perhaps incorrectly) that only RAIN damaged wood (not rising flood/tide waters).