The main difference is that high build refers to the property of a paint (‘can be applied at high thickness’), while high solid refers to the composition of the paint (‘contains less solvents’).

Coating formulations generally consist of three major components: A resin (such as epoxy or polyurethane), pigments (for corrosion protection and colour) and solvents (to make a liquid that can be applied on a surface).

By carefully choosing the major components and adding special thickening agents, the formulation can be made suitable for application at a relatively high thickness (high build properties). There are downsides, however, such as a reduced gloss .

For example: A glossy epoxy is typically formulated for a dry film thickness of 50 to 70 microns, while a high build epoxy is typically applied at a dry film thickness of 120 to 170 microns (or more).

High solid refers to the percentage of solvents in the formulation. By developing resins with a very low viscosity, the paint industry has been able to manufacture paints that need fewer solvents to attain the required viscosity. As a result lower volumes of paint are needed per square metre to obtain the same thickness.