Wet Rot can be caused where there is a moisture content of greater than 20%. It is most important to identify and fix the cause of the damp. An example would be a sub-floor pipe leak. Wet Rot can also occur where floor joist ends or wall plates are in contact with damp walls. Two of the most common fungi are: Cellar Fungus (Coniophora puteana) and Mine Fungus (Fibroporia vaillantii).