-
Step 1
New drywall: Always use a PVA drywall primer for new drywall. It will save you money--the first coat will really soak into the wall, and drywall primer is cheap. Priming the drywall first also ensures a more durable and washable finished surface.
-
Step 2
New interior trim: You can skip the priming on composite wood trim and of course pre-primed trim. You don't really have to prime new wood although it may save you some time. Wood primers do not "raise the grain" of wood as much as water-based paint will, and you'll have to sand a little more thoroughly in between the first and second coats.
-
Step 3
Redwood or cedar: This always has to be primed with an oil or shellac primer, no exceptions. These woods contain tannin, which will bleed yellow and brown stains right through any water-based paint.
-
Step 4
Exterior wood trim and siding: I suggest always priming this for a longer lasting job with either good acrylic or oil-based primer.
-
Step 5
Metal: Galvanized metal (like gutters) and aluminum usually needs no primer; just clean and paint. Iron and steel usually must be primed with a rust-inhibiting primer before painting.
-
Step 6
Painting white or light colors over a very dark or intense color walls: No primer necessary. Since most primers aren't designed to hide underlying colors well, most likely you'll just be adding an unnecessary coat of paint to your job.
-
Step 7
Painting intense or dark colors over a light wall: Check with the paint store when buying the paint. Most colors will only require 2 coats of paint--no primer necessary. Some colors in "neutral" or "accent" bases, like some reds, will require a colored primer or you'll be doing up to 6 coats of paint! They will be able to tell you when you buy the paint whether you need primer.
