An ABIS inspection includes the identification and reporting of corrosion to structural components of the dwelling.

In addition to structural members of ferrous metal such as steel post & piers and steel frames, there are other items such as supports, stirrups, fastenings and brackets in dwellings constructed primarily from timber or masonry which may be structural elements

For corrosion or rust to occur, both oxygen and water must be present. Application of paints or other coatings protect surfaces from direct contact with air and water.

Corrosion can be defined as the disintegration of a material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means a loss of electrons of metals reacting with water and oxygen. Weakening of iron due to oxidation of the iron atoms is a well-known example of electrochemical corrosion. This is commonly known as rusting. This type of damage typically produces oxide(s) and/or salt(s) of the original metal.

Most structural alloys corrode merely from exposure to moisture in the air, but the process can be strongly affected by exposure to certain substances (see below). Corrosion can be concentrated locally to form a pit or crack, or it can extend across a wide area to produce general deterioration. While some efforts to reduce corrosion merely redirect the damage into less visible, less predictable forms, controlled corrosion treatments such as passivation and chromate-conversion will increase a material's corrosion resistance.

Galvanic corrosion

A common example of galvanic corrosion is the rusting of corrugated iron sheet, which becomes widespread when the protective zinc coating is broken and the underlying steel is attacked. The zinc is attacked preferentially because it is less corrosion resistant. With a tin can, the opposite is true because the tin is more corrosion resistant than the underlying steel, so when the coating is broken, the steel is attacked preferentially.