Hi", Hoddges, who gave the name Poria Incrassata,? I can give name like : Poria Vaillantii ( France)it is a common species in wet mines but some times occurs also in buildings where the timbers have been exposed to very damp conditions, it needs a higher moisture content more that Merulius Lacrymans ( Dry rot). Poria Monticola Murr. is found in North America in Douglas fir, and Sitka Spruce if the timber in well ventilated the fungus will dry out.
let me know what kind of fungus you have, because there are over sixteen species which are in a group of fungus called Basidiomycetes. if you can find out what kind you have I may be able to help. But a hint: if it a poria type of fungus, then you should well ventilated and dry this will help to dry out the timber thats all I can tell you for the moment till I get some feed back from you. John 2000