As the days become cooler through autumn and into winter, the application and proper curing of latex and oil/alkyd paint can be significantly affected by low air and substrate temperatures and increasing moisture levels.
Latex Paint:
Air Temperature - The proper formation of the paint film can be seriously affected if paint is applied when air temperature is below 50° F. Paint film may crack and check, and improper film formation may cause a powdery film that can be brushed off the substrate. This can cause the touch-up coat to look several shades lighter than the base coat.
Moisture Levels - The moisture level in the air increases as temperatures drop during the fall which can cause large amounts of condensation to form on exposed surfaces. If the condensation forms on a paint film that has not fully cured, it can cause surfactant bleed or shadowing, primarily in deep and accent colors as evidenced by glossy, dark streaks or blotches on the paint film. Condensation can also dramatically slow the dry time and cure time of the film, increasing the water sensitivity of the paint film until it has fully cured.
Substrate Temperature - When surface temperature of the substrate is below 50° F it can significantly slow the drying time and even prevent proper film formation of the paint. It is important to note that the surface temperature can vary between different areas on the same structure causing the dry time and proper film formation to vary as well.
Paint Temperature - The performance of the paint can also be affected by the temperature of the paint when it is applied. Store the paint in an area that will be at least 50° F. If the paint is applied when it is too cold it will not flow and level properly, leading to excessive film build, thereby slowing the dry and cure time of the film.
Oil/Alkyd Paint:
Air Temperature - Oil/Alkyd paint is to be applied when the air temperature is 40°F or above. If the paint is applied when air temperature is below 40° F the paint film will take significantly longer to dry and thoroughly cure.
Moisture Levels - High humidity and fog conditions create problems for oil-based products, specifically heavy-bodied oil-based stains. If these products are applied in humid, foggy conditions, the paint can turn blotchy or show color differences in the film; we do not recommend the application of oil-based stains under these conditions.
Substrate Temperature - The minimum recommended substrate temperature is 40° F for the proper application of oil/alkyd based paint. The paint will be slow to dry and cure if it is applied below 40°F. Often, in order to warm the surface of cold walls to proper application temperature, room temperatures are raised well above normal levels causing other problems to occur including premature skinning of the surface of the paint. The premature skin will trap the solvents in the paint and dramatically slow the dry time.
Paint Temperature - The temperature of the paint at the time of application can greatly affect the drying rate of the paint film. If the paint is stored below 40° F and then applied at the same low temperature, it may not have proper flow and brushing characteristics, resulting in excessive film build and lengthy dry and cure times.
