Do I Have To Use A Primer Before I Paint?

Painting tips for doing it yourself . . . or checking up on your painter/contractor
Washington DC and Northern VA

The short answer to this question is short indeed.
Yes.
You should pretty much always use a primer (or “prime coat”) for any interior or exterior painting project.

A “primer”, or “prime coat” – for those who do not know – is the first coat of paint in a multi-layer paint system.  It’s the layer of paint that is applied directly to the surface that you want to refinish, and it goes underneath at least one other layer of paint, which is known as the “topcoat”.  Primers and topcoats are usually sold separately (although there are brands of paint which claim to do both), and they have subtly different physical and chemical properties.

Unlike the topcoat, which gives the paint its final look, feel, and resistance to the elements, the primer coat plays a structural role, rather than an aesthetic one.  The primary job of the prime coat isn’t to look nice; it is to adhere powerfully to the wall or ceiling, creating the ideal surface for the topcoat to stick to.

See, painting, when you break it down, is the art of getting a substance (the paint) to stick to a surface (your wall) in a thin, strong film, defying the laws of gravity.  Chemists and engineers have put years of their lives and millions of dollars into designing the substances that will do this best – and yet failure to adhere to the substrate (i.e., stick to the wall), is still the number one overall cause of paint failure, and probably always will be.  That’s because paint is designed with the ‘perfect surface’ in mind – but the surfaces that exist in our homes and offices are in reality very far from that perfect surface.  Our real-life surfaces are old, worn out, flaking, chipping, chalking, full of too much moisture, subject to temperature and humidity changes . . . in short, forever in the process of falling apart.  A good paint job can check that progress – but only if the paint can overcome the imperfections that already exist in the surface and really stick to it.

A primer is designed to do just that.  A good primer will be engineered to stick to the surface and hide whatever is on it – and that goal will be prioritized over anything else.  And believe it or not, paint is usually engineered as a balance between multiple goals: brightest color, strongest UV protection, best mildew resistance, longest durability, lowest VOC content . . . the list goes on and on.  You will want to pick a topcoat that excels in many of those categories – but let your prime coat just do its one job as well as it possibly can.

There are brands of paint out there (Duration by Sherwin Williams is a good example) that claim to be “one coat only”, and therefore not need a primer.  Many of these paints are very high quality indeed – and cost top dollar as well.  Our take on high-end no-prime paints: yes, you do get what you pay for when it comes to paint, and those top-dollar paints are indeed of the highest possible quality.  They are designed to perform well in all the ways you would want out of any paint film, primer or topcoat.  But for any less-than-ideal surface (raw and unpainted material, old and flaky existing paint job  – and again, in our experience, most surfaces are less than ideal), we would still recommend throwing a prime coat underneath.  A coat of Duration can fail on an unstable surface, too.  So why risk it?  Just pick the type of primer that matches your substrate, go for a trustworthy but slightly less designer topcoat, and be on your way!

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