You're sitting in your newly-built home or remodeled room and looking at the finished drywall. The joint between each piece of drywall is visibly covered with joint compound and drywall tape. You're ready to begin painting, but first you must apply polyvinyl acetate (PVA), a primer that seals the drywall.
Purpose of PVA Primer
PVA primer is a latex-base product that seals the pores of the drywall. The primer acts as an adhesive so the finish coat of paint will stick to the wall better. Even though the PVA primer hardens, it is still soft, which allows the finish color to stand out more and go on smoother. Without the primer, you will have to put several coats of finish paint over the drywall because paint does not wet or seal the surface of the drywall as well as the PVA primer.
It is important to remember that the PVA primer can be tinted to match the color of the finish paint you plan to use. Tinting the PVA primer will allow the finish coat of paint to cover the wall better. The amount of tinting can be half the color of the finish coat. A darker finish coat color will require you to place a gray tint in the PVA primer.
Fine Home Building recommends that you use the same brand PVA primer and finish paint. If you use a Sherwin-Williams paint, then you should use a Sherwin-Williams PVA primer. Manufacturers use ingredients in both the primer and paint that will give you better coverage when used together.
Once you have applied the PVA primer it's best to put the finish coat of paint on within two days. Beyond two days the PVA primer loses its integrity. If you wait longer than two days the primer can harden and crack. You will need to apply the primer again if you wait too long.