The previous owner told me that during the last winter when snow melted, water got in the basement through the drywall and he had to wipe dry the floor. Last year we had one of the worst winters on record (New York City).
I have a closet where a piece of the drywall (2x3 ft) has some black spots on it and water marks, but the rest of the drywall seems fine. The basement has regular drywall (not the blue one).
The basement doesn't smell musty or bad at all and I have not seen water coming in since then. I am planning on pouring concrete on the outside to take care of water that might be seeping through to the foundation.
If I just remove that small piece of drywall that has some black spots (mold?) on it, should I continue ripping off the rest of the drywall to look underneath? It would mean I would have to destroy the walls etc. what is the best route especially since the basement doesn't smell and I haven't had any issues since and the rest of the walls seem fine.
When I replace the drywall should I spray some stuff inside to kill the mold?