The main source of confusion surrounding primer is in how it differs from paint. After all, both products come in the same-shaped cans and are designed to coat a given surface. But while paint and primer are similar in many ways, they’re distinguished by chemical composition. In layman’s terms, paints are pigment-based while primers are resin-based. Resins actually penetrate a surface, filling its pores. Therefore, primer acts as a sealant. The pigments in paint do not share this quality, but instead provide color and add durability.

Why Does Primer Matter, Anyway?

So, we’ve now briefly discussed what primer is and how it’s different from paint. But we still haven’t explained why commercial and residential interior painting companies deem it so important. Of course, the information above might already give you an idea.

As mentioned earlier, primer acts as a bonding and sealing agent. By soaking into the surface, the primer creates a barrier that makes it easier for the ensuing paint to stick. Without this initial undercoat, some of the paint itself would get absorbed into the surface. This can damage the surface and reduce the quality and appearance of the paint job. So, the benefits of primer are threefold: it protects the underlying surface, helps the paint stick, and increases the paint’s durability.

Exterior and interior painting contractors may also use different types of primer on different types of surfaces for maximum protection and paint adhesion.

Is Priming Always Necessary?

In short, no, priming isn’t always a must. Some occasions don’t necessarily call for this step. For instance, if you’re touching up a previously painted surface that’s in good shape, you or your local interior painters should be fine simply cleaning and painting over it. Otherwise, though, priming is an important measure for achieving the best results.

As a rule of thumb, you should always prime before painting: