Undercoat

An undercoat paint is a type of paint that is applied as the first coat on a surface before the final paint coat. It serves as a base for the topcoat, providing a smooth and even surface for the topcoat to adhere to. Undercoat paints are usually applied on wood, metal or masonry surfaces, and can also be used as a sealant to block stains, tannins, and other discoloration from bleeding through the final paint coat.

Undercoat paint is usually formulated to be more porous than the final coat, allowing it to grip the surface better. It also helps to fill in small cracks, holes and uneven surfaces, providing a smooth surface for the topcoat. It is also typically less glossy than the final coat, but can come in different finishes such as semi-gloss and satin.

It is important to use the right undercoat paint for the surface and the final paint coat. Some undercoat paints are formulated specifically to be used with oil-based or water-based paints, others are formulated for use with enamels, gloss or other specific paint types.