Disintegration of concrete can occur even though all of the will known principles for producing quality concrete are followed closely. In some cases, concrete of uniform high quality is all that is needed to resist an attacking agent, but in others special surface treatments are essential. There are four main agencies that attack concrete. These are acids, oils, sugars, and coal. Concrete is not resistant to acids because the calcium it contains is attacked by them. Hidden acids, such as those produced by bacteria growth, are frequently more damaging because often time their presence is unknown. Frequent flushing of a smooth concrete floor is desirable. Oils have proved to be major problems in such places as slaughter houses, processing rooms for lard and bacon and bakeries. The best protection is coating the floor with linseed oil. Sugars will prevent the concrete from becoming hard and sugar solutions are very corrosive. The best form of protection is to allow the concrete to become sufficiently hard by aging it for at least 28 days. Coal itself is not a problem but sulphur it can contain is. When the sulphur combines with water it turns into an acid. The best defense then is to avoid moisture.