Fungi and mushroom growth can be recognised by the black or white fungal threads and mycelia, or by the fruiting bodies, the mushrooms. In most cases, it concerns house fungus (Serpula lacrymans) or cellar fungus (Coniophora puteana).
Fungi usually develop in and on wet wood and can spread quickly. That is why it is important for any fungus infestation to be dealt with professionally. So call in a pest control company.
After combating the fungus infestation, the cause must be tackled properly. This is often rising damp.