Choosing a Protective Coating for Structural Steel Components

Many structural steel components are intended to be left in situ for an extended period of decades or even centuries. It is important to ensure that these components stay structurally sound for that period, which is why many customers will elect to use a protective coating on their structural steel. Here are some of the options for protective coatings on structural steel. 

Painting

Painting is one of the simplest protective coatings and can protect the steel from scratches and light mechanical damage, as well as corrosion from the air and water damage.  It is important to ensure the surface is clean of debris or moisture before the paint is applied, or corrosion may start at the point of the trapped moisture or dirt.  Paint tends to wear or peel off over a period of time so is best suited to applications where you can regularly repaint (places with reasonable access). Newer peel-off paints can be a great option to reduce the labour and time associated with removing the old paint each time you repaint.

Plastic coatings

A similar but more permanent option is to use a plastic coating. These are usually created by dipping primed hot steel components into plastic beading, which then melts and forms a tight coating to the steel components. This can be a sturdier and longer wearing coating than painting but can be hard to repair if there is mechanical damage to the plastic. A loss of full coating coverage can make the component vulnerable to corrosion. As a result, it is suited to regions that have some susceptibility to corrosion but little wear. 

Metallic coatings

Metallic coatings help to protect the steel from corrosion, as well as extra mechanical damage protection. These tend to be more expensive than painting and also cannot be repaired in situ. This tends to limit the usage to either extremely corrosion prone uses such as uses in marine applications or in boilers and other hot applications. It is more common on small components such as screws and nails, which are often one of the riskiest areas for construction to fail. Common metallic coatings are zinc or chrome, which are applied by hot dipping components into a bath of liquid metal or using electroplating where the part is dipping into the bath and running an electrical current through the solution. 

Finding the right protective coating for your structural steel components depend on the application that you will be using it in, as well as your budget for the part and it's ongoing maintenance.