I found water stain on the laundry room ceiling. Then I went to the attic room to check the other side of the ceiling board and saw it is due to the pipe joint leaking. I can have the pipe joint glued but am not sure what the material I should use to repair the ceiling board from the other side that it has black mold due to the wet. Now the ceiling board has been dry but I need to fill and patch the ceiling board from the other side. Can you tell how to repair the ceiling board from the other side due to the wet? Thank you.