An undercoat is a is the first layer of paint applied on a surface prior to the application of the final layer of paint. It is also known as the primer coat. An undercoat prepares the surface for the application of the top coat. Most professional painters use a primer different from the top coat to prepare the surface. They then apply an undercoat which often has a neutral tone, before applying the top coat after the neutral undercoat has dried.

 

The undercoat makes the surface even to enable a smooth application of a top coat. It also gives a vibrant and much richer appearance to the top coat. Undercoats are utilized on wood and metal substrates. The undercoat prevents problems like rot, rust, and mold by providing an extra layer that protects the substrate from moisture. The undercoat also serves as a barrier against dents, scratches, knocks and other forms of damages.