I moved into a house from the 50s w/radiant heating in the ceilings. Not sure if the heating is electric or water running through copper pipes (original owner was a plumbing professor, so Im assuming the latter if such a thing exists). Ceilings are, I believe, plaster and/or lathe. I experienced drops of water dripping from the ceiling in one room today. Not sure if it's from condensation (possible since it's 90 degrees and very humid today) or if we have a leaking pipe. The area w/the drops of water has experienced deterioration (cracked plaster falling off the ceiling and the lathe layer visible) in the last few months. However, today is the first day water has been seen dripping from the ceiling. When touched, the lathe is coming down like sand. I don't know where to start to get this problem fixed. Do I call a plumber since I may be dealing w/copper pipes running through the ceiling? Do I call an HVAC person? My biggest fear is that there is no one out there anymore (they've either retired or are no longer on earth) w/knowledge of and/or experience with our type of heating and we'll be stuck w/having to replace the entire system. Any suggestions and/or info about what we're dealing w/and how to fix it would be greatly appreciated. If anyone has experienced this problem, would love to hear how you dealt w/it too. Thanks.