Maceration ( often referred to as wood corrosion ) is a not-too- frequent damage. It is classed as a so-called chemical damage. Maceration occurs when wood preservatives on the wood surface cause a chemical interaction with humidity. For example, saline special fire retardant paints or animal droppings of bats or birds causes acids on the wood surface that dissolve the wood lignin. It is no biological process but rather a chemical reaction. Also brickyard coverages together with a certain humidity in the air can interact together when then mineral salts from the bricks or the mortar react with the humidity and settles with as a fine film of acid on the wood. Recognizable is the fact that the wood is frayed cotton surface to about 1.5 cm deep through maceration
Often this is associated with a crystalline efflorescence of salts. Maceration may result in severe damage and may when large amounts of decomposing acid comes on the wood as thick layers of bat or bird droppings cover the woods for years.
This process can permanently be stopped when the main cause for this, the interaction of the elements leading to this chemical reaction is broken. Possible biological contamination by animal waste should be removed. Chemical coatings should be removed by sandblasting and replaced by alternatives. A change of building physics circumstances can lead to a slowing or stopping the wood corrosion.