If the surface you are about to paint is previously painted (previously prepared), and you are going to re-paint with a similar color and sheen of paint, then you may use a paint and primer in one product. In most situations, paint professionals would recommend that you use a quality primer before painting.
When To Use Paint and Primer In One
All in one paint and primer products work best when you are painting over a surface that is already painted. This is because the effectiveness of all in one paint and primer likely falls somewhere in between the traditional two-step process of priming then painting and simply skipping the primer all together.
When advising clients about painting, relators like to remind homeowners of the purpose of primer as a step towards selecting the right product. “Primer is formulated to work with the topcoat of paint to promote better adherence to the wall. This is important if you are changing the sheen from a slick semi-gloss to flat, or wanting to cover oil-based paint with latex.”
If you are covering an already painted wall with the same type and finish of paint in a similar shade, you may be1able to get away with avoiding the primer altogether. In these situations, Paint and Primer In One may help you get better results in just one coat. Paint/primer combo products may also allow you to get effective coverage over a wider variety of shades of existing paint.
When To Use Traditional Primers and Paints
Skip the 2 in 1 products when changing the paint type (including changes in sheen) or painting over a surface that has never been painted before. In these applications, traditional primer will do a better job of preparing the existing surface for the paint to effectively adhere. This is one area where the opinion of contractors and professional painters is decidedly against so-called self-priming paint.
*Owner of Tingle Painting, knows that 2 in 1 paint plus primer can work in certain situations. “I have used one of the all-in-one products on exterior wood trim and it worked really well. The trim was already painted.” However, he cautions that all in one paint and primer doesn’t work as a one for all blanket solution. “If you are working on a new surface such as new drywall or new wood, I would suggest using a good quality primer first.” Because paint tends to be absorbed quickly by new drywall, primer will not only create better adhesion, but will also save you from wasting paint (and money and time) on extra coats. For best results, use primer and paint of the same brand. *Noted from Dave Tingle