There have been a few times that I needed to get a paint job done, but I had no primer. I thought about just using the regular white paint that I had on hand just to get the job done. I wondered, can I use white paint as primer? Here is what I found out after doing some research myself.
You should not use white paint as primer, as primer has a higher concentration of solids plus it contains an adhesive binder and acts as a sealant. A good quality primer is designed to provide the final finish coat with a better bonding surface than the bare surface itself, unlike white paint.
White Paint vs Primer
A standard white latex paint is no substitute for a good quality primer
Primer seals the surface and provides a smooth and clean area for paint to adhere to. Primer is more like glue or sealant than paint.
This gives the final paint coat better adhesion to the material you are painting.
For many surfaces, the paint will last much longer if a primer is applied first.
Primer also acts as a sealer. The primer seals the surface material so that the final color paint coat doesn’t soak into it, which would require extra coats.
In general, it is always a good idea to first use a good quality primer to help achieve a consistent appearance with your final coat. Using a quality primer is typically much less expensive per gallon than using multiple coats of quality interior latex paint. If you choose the correct bonding primer for your application, you will be sure to get great adhesion of your finish coat to the surface.
What happens if I don’t use a primer?
Not applying a primer to a surface that needs it will result in an early product failure which is also known as peeling.
Product failure will require that the paint be removed by scraping or sanding the peeling paint before applying the primer that should have been applied in the first place. Not using a primer will cost you time and money.
When do I need to use a primer?
There are times when using a primer is a must. Let’s go over 7 instances where primer is needed.
If the surface is porous
A highly porous surface requires a good primer to soak in to create a good surface for the final coat to adhere to. Newly installed drywall is highly porous. The bare facing paper on drywall and the dried joint compound covering the seams are very porous and will soak up paint. Painting masonry surfaces such as block walls, bricks and concrete retaining walls require a primer to achieve a consistent color for the final color coat. The primer will also allow for better adhesion for the final coat.
When painting bare wood
A good quality primer is a must when painting bare wood. Using a primer on bare wood will help with color consistency when applying the final coat. Applying a good quality primer seals in the natural tannic acid (or tannins) of the wood. If a wood is painted without first using a primer, the tannins that are in the wood can seep out and cause early product failure (pealing) of the paint.
Applying a primer to bare wood also helps to hide imperfections on the surface and helps to prevent bleed-through from knots and other natural blemishes and coloring in the bare wood.
When painting newly installed or skim-coated drywall
A new drywall or skim-coated surface is highly porous and thus requires at least one coat of primer before painting.
A new drywall surface will soak up paint like a sponge which will cause it to cover better in some areas than others. This is especially true when you’re comparing drywall mud joints to the surrounding areas. A skim coat is a thin swipe of drywall compound laid over bare drywall. It is typically used to even out a rough or uneven wall surface. The skim coat of drywall compound is also very porous and will require a coat of primer before the final color coat can be applied.
When the existing surface is glossy or very smooth
A surface painted with a high gloss paint does not hold successive coats very well. A light scuffing with sandpaper and a coat or two of primer will help the color coat stick. If the glossy sheen is not scuffed, using a primer will help subsequent coats stick. Ceramic tile, glazed block, plastic or vinyl shutters, and surfaces with a high gloss finish will usually require some type of roughening of texture prior to painting. Surfaces that are especially “slick” pose a unique challenge for even the best primers when trying to get a coating to stick to them.
When the existing surface is stained
Spotted or stained surfaces benefit from a coat or two of priming before painting. There are special primers designed for use when the surface is stained.
When you are changing color from dark to light
Use two layers of primer over a very dark color before applying a final lighter color coat.
Primer is usually much less expensive than the color coat which will save money.
Trying to cover a dark color by applying many layers of a lighter color will take more time and cost more money. Most paint retailers can tint your primer to the color closer to that of the wall finish color, which will reduce the number of primer coats and color coats you lay down.
When the surface has an odor
If the room you are painting had smokers, pets, or somebody that cooked strong-smelling foods, the walls likely soaked up and retained those odors. A high-quality primer will seal in and eliminate odors and prevent them from returning.
If you ask any homeowner who didn’t first prime over old smoke or pet odors, they’ll likely tell you that the smell came right back. The smell returned because regular paint doesn’t have the sealing properties to keep those old odors away permanently.
When do I not need to use a primer?
Using a good quality primer before painting a color coat is usually preferred, however, you can often get by without priming under any of the following conditions:
If the walls that were previously painted and are very clean
Walls that are perfectly clean and in good condition may not need primer. You may clean the walls using a mixture of tri-sodium phosphate (TSP) and water.
Wipe down the walls with a soft cloth damped with the TSP mixture. You can also use a vacuum cleaner with a clean brush attachment to clean off other debris like cobwebs and dust. Normally when painting over a previously-painted surface, you do not need to use a primer first. You may need to spot-prime any bare areas before applying your finish coat.
When you are painting a darker or similar color
If the walls are clean and the surface is in good condition, a primer may not be needed when painting a similar or darker color.
Can I use self-priming paint?
Self-priming paint is essentially a paint that is thicker than regular non-priming paint. Because it is thicker, it builds up higher and forms a thicker coat. The paint industry term for this thicker coat is called “build.” Self-priming paint builds up as it dries, which leads to a thicker layer than regular paint or standard primer.
Most self-priming paint can be used in a paint sprayer without thinning.
Regular primer itself is a relatively thin-bodied material. Primer is thin so that it will more readily soak into porous surfaces. Because self-priming paint is thicker, it doesn’t work as well on porous surfaces.
There are disadvantages to using self-priming paint. Because it is a thicker paint, the higher build makes for a weaker coat that takes longer to dry.
When do I need to use two coats of primer?
There are a number of instances where two coats of primer will be needed:
- When you are switching from a higher sheen to a lower sheen finish. An example is moving from a semi-gloss to an eggshell finish or a gloss to a flat finish.
- When switching from a dark color to a lighter one.
- If your walls have been repaired or patched.
- If you’re painting a humid area like a bathroom, which is more susceptible to mildew and leaching.
- If your wall has stains that you want to block. (an example is water spots from a bathroom leak or smoke damage from a fire in a kitchen).
- When painting unfinished wood trim or other very porous surfaces.
In summary, taking the time to properly apply a quality primer before painting will enhance the life of the paint. Primer provides a superior adhesion for the final coat and will result in a more professional looking job.