I recently remodelled my home and installed new roof - replacing old wooden beams with all steel structure.roof is then corrugated zinc which coated with black tar then topped with red tiles.I live in tropics - now rainy season here the new gypsum ceilings are showing black (damp ?)marks which could be caused by humidty being trapped in ceiling.when ceiling was installed they did not use any insulation could that now be the problem ??I am about ready to move into house before christmas so need to resolve this problem firstand don?t want to lift off roof again or remove ceilings.what could be the problem and how to resolve it ???
If you have black marks on your ceiling - it is MOLD and probably not good for you to be breathing. Unfortunately, you will need to tear out your ceiling and start over. It sounds like you may have a leak in your roof, or around where the flashing would go around the edge of the house (where moisture would get into it). Im not familiar with construction techniques in a tropical climate, but not sure that insulation would solve this problem either. Sounds like you need some sort of ventilation system in your attic area to manage the humidity. There is a product called kilz that is used for treating areas that may be prone to mold, but sounds like you already have it, so you cant kill it you will need to start over with your gyp ceiling. consult a contractor in your area who probably deals with this situation often.
i think its a moisture problem rather than leak probably where wall and ceiling meet you need ventilation attic vents do the trick also house may be sealed to good need a fresh air intake
