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What is Paint Primer Used for – Importance of Applying It

Maintaining ones’ house properly increases its lifespan and makes it look cozy and comfortable even after many years. The paint on the walls is important for making the house look good. When painting the walls, many face the dilemma of whether or not to paint primer on the houses’ walls. To know if primer plays a vital role in holding the paint, go on and know what does paint primer do and when to apply it for best results.

What Does Paint Primer Do?

Painting primer on walls before actual paint might seem like extra work to some, but this is not always the case. Primer provides a great foundation for a paint job if used as a base coat. This foundation makes the job of painting smoother and increases the longevity of the paint. Let’s see why should you use primer paint,

Stable Surface

Using primer paint on walls gives a stable surface to paint the walls properly. When the wall’s surface is too porous, the paint tends to be drawn into the surface itself. Thus, two or more coats of paint are needed to develop a thick layer of paint. The inverse of this situation is also a problem. When the wall’s surface lacks porosity, the paint is unable to lock onto the surface. Since paint prime is only a little rough, it provides a great texture for the paint to stick on.

Covering Stains

Paint primer helps in covering stains on the walls. The color coat can be freely applied after covering the stain with a base layer of paint primer. Since it costs less than paint, it is cheaper for the base layer of the wall to be of primer. Primer also blocks stains from bleeding through the painted finish.

Other Functions

Primer covers any imperfections in the wall that had been previously repaired. It has better adhesion than a plain wall, allowing the paint job to remain longer. Primer helps create a uniform layer, which makes painting the walls simple and seamless.

Primer has many features that make the job of painting walls very easy. It also makes future maintenance simple and allows the paint to last long.

When to Use Paint Primer on Walls?

Primer is not necessary before every paint job. This is because not all walls require a coating of a porous substance to let the paint stick to the wall. Most manufacturers still recommend that at least one layer of primer be added to any wall. This helps in providing longevity to the paint. Check out the below list to know when to apply primer,

  • Skim-Coating on Drywall: When a slim layer of drywall compound is laid over the bare drywall, it is called a skim coating. This is the highest possible grade of skim coat and not something customarily applied. This type of finish is highly porous and requires at least one coat of paint primer.
  • Porous Surface of Wall: Walls with a surface that is too porous need a primer coat. These have a bare-facing paper on the drywall or are made of plain wood and are examples of porous surfaces. Walls made of simple bricks, blocks, and even dried joint compounds on the seams need primer coating.
  • Not Enough Porosity: Like too porous walls, lacking in porosity is also not suitable for the wall. Not being porous enough on the wall’s surface means that the wall might be too glossy. A glossy wall cannot lock onto the paint. Using a primer, the glossiness of the wall can be removed to reach the required porosity.
  • Contrasting Paint: Situations when there is a bit too much contrast between the paint coat and the color of the wall need paint primer. In such cases, it is recommended to apply two to three coats of primer. For example, if the color of the wall is black and it needs to be painted white. In such cases, painting multiple coats of expensive white paint to get the proper color is not as good as just a few layers of primer. Tinting the primer slowly towards the required color will help when putting the final coats of paint on.
  • Stained or Repaired Surface: Walls that have been previously repaired or have stains on them benefit a lot from multiple coatings of primer. The primer helps make the repaired surface more even and hides stains.

Not all walls are the same, and not all require the same coating for primer. Some walls will require one or two coats while others may not need even one. Therefore, it is essential to understand the properties of the wall before deciding if a primer coat is necessary or not. In case of any confusion, it is best to get the advice of an expert.

How Many Coats of Primer Do I Need?

Since not all walls are made of the same material, they don’t require the same amount of primer, if at all. The amount of primer needed changes based upon the condition of the wall, color, materials used, etc.

  • No/Low Contrast: A situation of low/no contrast happens when the color of the wall’s surface and the paint to be done are similar. For example, When a light yellow paint is to be painted upon a white wall. Walls with little to no contrast will likely need only one coat of primer before they can be painted upon.
  • Repaired, Wooden, or Bare Drywall: In these types of walls, the first coat of primer is usually absorbed by the material coated on the wall or the material of the wall itself. As such, two coats of primers might be required before these walls can be painted.
  • High Contrast: When the wall’s surface and paint have too much contrast between them, it requires multiple primer coatings. For example, when a dark colored surface is to be painted white. Usually, in such cases, two to three coats of primer are used to ensure the bonding between the wall and paint. The primer layers also help to cover the previous color of the surface.

That said, it is essential to remember that this is a general guide. All surfaces have very different situations that can only be recognized by knowing them. Thus, it is best to carefully consider the properties of the surface before deciding the number of primer coats needed.


Should you prime wood before painting?

It is not mandatory to prime the wood before painting. But if you are about to paint the unfinished wood, it is recommended to apply the primer as it prevents the paint from soaking up in to the wood.

Do I need to use primer on already painted walls?

If the painted wall is smooth and again you are applying the same type of paint, then it is not necessary to use the primer.


Hope you now understood the purpose of paint primer. It create a layer on top of the surface which is to be painted. Not all walls require primer but they do help retain paint on the wall for long periods. The amount of coats of paint primers required differs from surface to surface. The porosity of the wall, the color, the material of the surface etc. all affects the number of layers of primer required. That said, most surfaces can be painted quite well after just two layers of primer.