WHAT IS DRY ROT?
Contrary to popular usage, dry rot does not mean rot that can happen in dry wood, or wood that has rotted and dried out. Dry rot is a specific kind of fungus, although the term is very commonly misused to describe all wood rot. This is unfortunate, because it disassociates rot from moisture. Wood rot always requires moisture, and the key to wood durability is the control of moisture. Wood that rotted long ago and is now dry was moist at the time of the rot. The true dry rot fungus has the ability to tap into a water source and conduct water to what would otherwise be dry wood. However, it has to wet the wood before it can attack the wood. The true dry rot fungus is more likely to be found in buildings that contain brick or stone than in all-wood buildings.