Condensation between joist?

I have a 2nd story condo facing the gulf of Mexico. It is July, and the air is very humid. When I go from the condo to the outside, my glasses fog up instantly. Recently, two sheets of sheetrock over the front door (facing the beach), fell. The sheetrock did not have any mold on it. The sheetrock was simply moist and crumbly. Upon inspection, the entire front of my condo's sheetrock (about 3-4 sheets in) are sagging and getting ready to fall. The sheetrock paper is no long strong enough to give the screws holding power. The 5th sheet and further back are fine. No water source is near the front of the condo. The front of the entire building is under a covered deck from above, so rain water leaking through the door is unlikely.
The floor in the unit above mine has soggy floors in the same area; entire front of the building, about 8' inward. We took out the vinyl flooring, and the subfloor underneath is dry rotted in some places. There is dripping water on the bottom side of the subfloor. The top of the subfloor is wet. Again, the subfloor towards the back of the condo is dry.
- There is insulation between the joists, paper side towards the sheetrock. Although I don't think they seal the entire 12" space (2x12 joists).
-We have hosed down the front and side of the building hoping to find water leaking through, but have not seen water penetration from windows or doors.
-Chlorine tested the moisture, and there's no Chlorine, indicating that it didn't come from a city water source.
- Both condo's mine and unit above are air-conditioned for most of the summer.
- The insulation paper is wet and so is the top 1-2" of the insulation facing the subfloor. But the insulation in the middle is relatively dy.
-The best way to describe the area between the subfloor and the sheetrock is a cave that is dripping water from the surfaces.
I'm at a loss in finding the "source". Could this really be condensation? Enough to cause water dripping from the subfloor and forming on the sheetrock surface? What are some ways to test, and prevent this. I plan on taking my sheetrock down and doing something about the space between the joist, if this is the real problem.
Please email with your suggestions. Thanks, Tim
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Too many possibilities. 1. One is that there is leakage of rainwater through nearby, or overhead windows. Rain has a way of getting in that is not always revealed by water hose testing. Are the windows properly flashed at the top of the trim with Z-flashing or similar galvanized sheetmetal. Are the windows and doors properly installed, with good house wrap or moisture proof sheeting between the siding and the plywood backing on the exterior of the house? 2. Another possibility is a/c air leaking into the walls or subfloor via a leaky duct, that would get things wet in a hurry, due to condensation. 3. Poor insulation in the walls, or around the a/c ducting. 4. Slow water leak from roof or plumbing, leaking into the house in a very circuitous path. Finding no chlorine is not definitive, since it tends to come out of the water, over time.Roof leaks and window leaks tend to stain the ceiling and wall sheetrock since it passes thru wood, picking up tannins, etc.
You need to keep following the water damage up thru the upstairs condo, until you find a source. I think the wet floor upstairs is not the source. Good Luck, Roger
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"Roger Taylor" <sherryrogeratcomcastdotnet> wrote in message

porous and water will work its way through in some cases. With a serious problem like that, I think you need expert on-site inspection and advice.
Don Young
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snipped-for-privacy@gmail.com wrote:

Could you have any leaking duct work in the attic?
If you do, then it could cause condensation in the attic.
--
Moe Jones
HVAC Service Technician
  Click to see the full signature.
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Your building has major structural deficiencies, could be bad design, faulty construction, termites, etc., or a complex blend of many things. Solving the problem could well be beyond your individual financial means. But being a condo usually implies a condo association which is responsible for the structure. If this is the case, then having a professional structural engineer on the job would benefit everyone. Consider the ramifications of continuing to live in a damaged building, then decide on your best move (literally). HTH
Joe
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Sounds like your condo association / insurance company needs to be contacted so they can deal with this common area problem. It isn't your issue to solve.
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