Chemical attack of wood

Damage caused by chemicals can be mistaken for attack by wood-rotting fungi. It can be caused by acid or alkaline chemicals, commonly from industrial atmospheric pollution, leaking flues or salts eluting from tiles or lime mortar torching. It may be associated with corrosion of metal fastenings, often called 'nail sickness'. The commonest form is sulphate attack of roof timbers - the wood surface becomes defibrated and may be covered with powdery crystals, not unlike fungus mycelium, but which will crumble when they are touched or brushed. The attack, while usually superficial, may be widespread.