What is an Undercoat?

An undercoat, also known as a primer or base coat, is a preparatory layer applied to a surface before the final coat of paint or finish. It is typically used to enhance adhesion, promote even coverage, provide a smooth surface, and improve the durability and longevity of the topcoat.

The primary purpose of an undercoat is to create a suitable surface for the application of the final coat. It helps to seal the surface, preventing the absorption of the topcoat into porous materials such as wood or drywall. This prevents the topcoat from appearing blotchy or uneven and ensures a more uniform and professional finish.

In addition to improving adhesion and surface quality, an undercoat can also provide other benefits depending on the specific type of product used. For example, a primer can act as a barrier to prevent stains or tannin bleed-through from wood surfaces. It can also block odors, inhibit rust formation on metal surfaces, or provide a suitable base for specific types of finishes such as enamel or lacquer.