I have a 2 story brick house in St Louis (and it gets hot and humid here in the summer). It's a 100 year old house with a flat roof, and has a 4 ton AC unit. The AC unit and Heat exchanger and everything else in the basement is about ten years old. I have my HVAC guy come every year and service it.
In addition to the AC, I run a dehumidifier in my basement in the summer. I figure that helps keep things dry and takes some strain off the AC (feel free to correct me on this).
The second floor was rehabbed about 15 years ago and the ductwork was run along the ceiling and has a drywall bulkhead built around it.
For the last 2 or 3 years the drywall bulkhead upstairs has been dripping and has just gotten worse. Last summer I ripped out some of the drywall around the ductwork hoping it would stop the condensation. However, the condensation never went away. I discovered the ductwork is totally uninsulated.
So I am ready to do something about it before summer comes again. I have read as many threads as I could find here regarding condensation and I didn't see my exact situation dealt with (lots of problems with crawlspaces though).
The first 3 or 4 years in this house there were no signs of condensation. Would something cause this condensation to start happening? What is a good way to remedy this problem?
I guess one more thing, the roof was leaking last spring. I had a new roof put on and no more leaks. And the condensation kept happening. So I am pretty certain there is no source of moisture other than what's in the air.
Sorry for the long post, just trying to give as much info as possible. I appreciate any advice I can get.