Choosing the best interior paint for a project is important. One of the most common questions we get asked is if we will be using a paint with primer, or if we will prime before we paint. We look at the difference between the two methods, when to use them, and when they are unnecessary..
What Does Primer Do?
Adhesion – The main purpose for using primer is to improve the bond between the surface and the paint being applied. Without good adhesion, the topcoat can lift and peel easily from the surface. The chemical makeup of primer allows it to bond better with the surface beneath. This allows paint to stick to surfaces it would otherwise might not bond with.
Stain Blocking – The qualities of primer make it very useful for sealing a surface and blocking stains and tannins from bleeding through. Water and smoke stains can easily show through regular paint, discoloring the fresh coat you just applied. Sometimes it takes several days or weeks to show, but these eventually come to the surface through regular paint when a primer isn’t used.
Odor Blocking – The paint on our walls can act like a sponge, soaking up substances from the air around them. In the process, they also soak up any odors. No matter how much you clean, you can still smell things like cigarette smoke. Most modern primers do a good job of sealing those odors in. There are also now odor-reducing paints on the market, though we still recommend using a primer first for areas that need heavy treatment.
What About Paint With Primer?
You’ve undoubtedly seen paints that already include primer as part of their formula. These paints are naturally a little more expensive, but have many benefits. The main reason for using a paint with primer is for the hidability. This basically means that it does a better job of obscuring what is being painted over.
Painting a room with a new color, or have really dingy walls? A paint with primer might be exactly what you need. Many of the high-end paints we use for interior and exterior work have primer in them. While more expensive than standard paints, it typically goes on with less coats than just regular paint which saves in labor. In most cases, just a single coat is all that is required, even for a modest change in color.
Some of our favorite paints have primer in them. The majority of our interior and exterior work is done using Sherwin Williams Superpaint and Behr Premium Ultra. Both are high-quality paints that include primer in the formula.
When Should You Prime First?
Even with hi-tech paint, there are still circumstances where using a separate primer first is a good idea:
Raw Wood – Raw, unfinished wood should always be primed separately before painting. Wood tends to absorb the various compounds in paint at different rates, causing uneven drying and finish. Using a primer first eliminates this problem by sealing the wood.
New Drywall – Paint is expensive, and fresh drywall absorbs it like a sponge. If you’ve had new sheetrock installed or have put a new texture on your ceilings or walls, then a good drywall primer should be used to seal the sheetrock before painting.
Masonry – Masonry (brick, concrete, etc) should ALWAYS be primed first before painting. The porosity and chemistry of masonry makes it difficult for paint to go on and adhere. Specialty masonry primers can seal the surface and overcome the high Ph levels present, helping paint go on smoother and last longer.
Stains & Odors – In areas with excessive stains or heavy odors, using a separate primer will help seal these before painting with the finish coat. Smaller stains can usually be covered by paint with primer, but larger areas should be primed first.
Drastic Color Changes – Use a separate primer when changing the color drastically. Especially if you are going from a dark color to a light one, you will need to seal the surface so the old color doesn’t show through. This is also true if the original color is very bold or bright, such as a deep red. A paint with primer might get the job done, but it is safer to just prime first.
Painting Over Paint
As a general rule, you do not need a separate primer if you are painting over a previously painted surface. As long as the surfaces are in good condition, most paints will easily go on top. If you are drastically changing the color or have odors or stains you are trying to block, then a primer might be in order. Otherwise, a paint with primer will suffice in most situations.
