I had a store in Jeff City need it’s windows caulked … they noticed that the black stuff on the wall was growing and …hay! The floor is wet!
I repaired a shorting front door light switch that had mold growing out from under the wall plate by a 1/2″ … because the gutter just outside and above the window was not caulked properly and allowing water to pour down the wall and into the un-caulked cracks of the window… into the wall… into the electric box!
I had a person with water coming into the house… repeatedly making the carpet wet and …what’s that smell???? MOLD perhaps! Why Yes! So let’s caulk that window right outside … the one with the large gaps.