I had my summer home in Connecticut repainted by a professional last year. I now have 2 gallons of latex primer left over. I don't want to dispose of it if I can avoid it and I can't return the paint as I have already had this paint tinted to match the same color as the house (dark gray). The exterior of the house is wood shingles. Can I paint over the top coat, which is also a latex paint, as a way of safely getting rid of this excess paint. Will putting a primer over a top coat affect the top coat in any way?
Tom In Connecticut
Absolutely not. Primer and top coat have different qualities. Primer is the "glue" that makes the paint stick. It is designed to adhere to the substrate and level out the surface in preparation for the top coat. It has no ability to resist UV. That is the job of the top coat.
Why don't you donate this extra paint to a worthy organization? Primer always comes in handy, regardless of whether it has been tinted or not.