first floor ceiling leak
I have this mysterious leak on my first floor ceiling. The leak occurs a day or so after it rains or snows. It is a slight drip about an inch or so wetness on the ceiling. And it is a foot away from the outerwall. It does not happen on the day of the rain or snow, but a day later. And if there is still snow outside, the leak continues. But if there is no wetness outside, then there is no leak. I recently got my roof done, but the leak is still there. There is a bedroom upstairs and no bathroom close by. I went into the attic and everything is clean there. There is a ABS pipe that is going down from the attic to the outerwall around the area where there is a leak. Could it be condensation from that pipe?? Not sure what to do. Any help or advice, I would be grateful.