Latex primer is preferred for most interior surfaces because it is easier to apply, less messy and lacks the offensive odor that emanates from oil-based paints. In addition, latex primer offers greater compatibility with interior paints. However, there are certain surfaces around the home that will reject latex primers. In these cases, oil-based primers are not only the preferred base coating; they are the only suitable option.
Latex primer is the appropriate base coating for unfinished interior wood surfaces. Although oil-based primer can be used on these types of surfaces, it is generally not preferred, because it is incompatible with latex paint. Unfurnished exterior wood surfaces should be coated with acrylic latex primer, because it offers greater elasticity as a defense against varying weather conditions.
Oil-based primer is the appropriate base coating for stained wood surfaces. Water-based latex primer will not adhere to stained wood because the stain is oil-based. Latex primer will eventually chip and peel from stained wood surfaces in the home.
Rusted metal in and around the home requires an oil-based red oxide primer to effectively prevent recurrence. Latex primers should not be used to coat rusted metal surfaces, as they will allow the rust to continue to spread.
Surface preparation is vital to primer adhesion. A tack cloth should be used to remove sawdust from wood surfaces. A pressure washer should be used to clean exterior surfaces. Inadequate cleaning can lead to primer adhesion problems.
Primer is generally only required for unfinished surfaces like bare metal, wood, plastic, vinyl and fiberglass. Drywall requires neither a latex nor oil-based primer. Previously painted interior and exterior surfaces also do not require primer.