It depends on what you are starting with. Bare stucco always needs primer. Chalky or aged stucco needs a conditioner. Fresh wood that is exposed on fascia or trim needs primer. Sound existing paint in good condition on a same-color repaint is a situation where you can sometimes skip it, but it is not the default and it is not always the right call.
Here is how the exterior painting team at Color Masters Painting thinks through the primer decision on every job.
Bare Stucco: Always Prime
New stucco is alkaline and porous. Put paint directly on it without primer and you get adhesion problems, color inconsistency, and a surface that is going to need repainting far too soon. We use Sherwin-Williams Loxon primer on bare stucco. It is a masonry primer designed specifically for this, and it is the right product for the substrate.
Chalky or Aged Stucco: Use Loxon Conditioner
Chalky stucco is different from bare stucco. It has paint on it, but that paint has degraded to the point where the surface is powdery and loose. Standard primer does not solve that problem. You need a penetrating conditioner that stabilizes the chalk before anything else is applied.
Sherwin-Williams Loxon Conditioner is what we use on these surfaces. It soaks in, binds the chalk, and gives the topcoat something solid to adhere to. Skip this step and the new paint will eventually pull the old degraded layer off the wall with it.
Bare Wood on Fascia and Trim
Exposed bare wood on fascia boards, window trim, or soffit gets an exterior wood primer before topcoat. Wood is a different substrate than stucco. It absorbs differently, it moves differently with humidity and temperature, and paint without primer on bare wood will fail at the edges and end grain first.
What About Rust Spots and Metal?
Rusted nail heads and small metal spots get treated and primed with Rust Destroyer before topcoat goes on. You cannot prime over rust staining and expect it to stay covered. The rust has to be treated or it bleeds back through.
Sound Existing Paint
If the existing paint is in good condition, properly bonded to the surface, and you are repainting with the same color, spot-priming bare areas may be all that is needed. But if there is a significant color change, if the existing paint has any adhesion issues, or if there are a lot of repaired spots, full priming is the better call. We make that assessment on every job.
The Short Version
Primer is not a step to skip to save money. It is what makes the paint last. We would rather use the right primer on the front end than have a customer call us because the paint is peeling two years in.resin
Color Masters Painting handles all of this correctly on every job in the Daytona Beach and Port Orange area. Contact us for a free estimate.