I have a wet spot on my kitchen ceiling. This is the second one. The first time I called our plumber cause the pipes are in the attic. But he said the pipes weren't wet, there was no leak. It dried up but left a stain. Plus it had not rained. Now another one appeared. This time called the air cond. company to check if unit is draining correctly. It's fine and no condensation on the duct work. I looked myself. There's definitely a wet area on the drywall. The insulation isn't wet on the top layer, just on the bottom next to the drywall. It is under an elbow joint in the pipes but again the pipes were dry. Where can the moisture/water be coming from? And who should I call, a different plumber, a contractor or what? I'm at a total loss. I can't believe the pipes would sweat that much Help anyone?