Hyphae and Mycelium are the only true Dry Rot fungus and have the unfortunate ability to grow through (not merely over) damp porous masonry in search of further cellulose based materials (such as timber) to feed on.
Eradication usually involves extensive removal of plaster, masonry sterilisation, replacement of timbers and the removal of actual and potential sources of moisture ingress.
ALL actual and potential sources can include: