Why is it necessary to apply a primer before painting drywall?

Applying a primer before painting drywall is essential because it enhances adhesion and provides a better finish. Primers are specifically formulated to create a smooth, even surface that allows the paint to adhere properly. This is particularly important for drywall, which can be porous and may absorb paint unevenly without a primer.

Additionally, the use of a primer helps to seal the surface and can improve the overall durability of the topcoat. It can also help in preventing issues such as peeling, chipping, or flaking paint over time. By providing a uniform base, primers ensure that the colors of the topcoat appear more vibrant and true to the desired shade. This leads to a more professional-looking final product and extends the lifespan of the paint job.

While other options may touch on aspects of painting or drywall treatment, enhancing adhesion and achieving a quality finish are the primary purposes of using primer in this context.