Quick Takeaways Known as the “House-Eating Fungus”: Poria incrassata (or Meruliporia incrassata) is a highly destructive wood-destroying fungus that causes brown cubical rot, crumbling floor joists, subfloors, and support beams. Transports Its Own Water: Unlike typical mold or dry rot that requires damp wood, Poria incrassata uses vine-like strands called rhizomorphs to pump water from wet soil or leaks directly to dry wood—allowing it to