This is a type of wet rot that can resemble Dry Rot
The wet rot Fibroporia vaillantii is a type of wet rot that can resemble Dry Rot Serpula lacrymans.
Fibroporia usually only needs treatment like any other type of wet rot outbreak i.e. remove the source of moisture and replace the weakened timbers. If it is mis diagnosed as a dry rot outbreak it is possible that a lot of unnecessary work could be carried out.
These pictures are from a bathroom where a water pipe had been leaking very slightly for several years. When the builder exposed it he then called us in to sort the ‘dry rot’ problem out.
Result: one correct diagnosis, one happy customer, one happy builder.