What Is Primer Paint? Why Is It Necessary?

Jan 24, 2023

Are you planning to refurbish your home or office? Have you been suggested to use primer paint on your walls? Are you confused about whether or not to apply primer before the paint? 

To use or not to use primer over paint is an age-old conflict. While some speak in its favour, others consider it a complete waste. The decision to use primer paint generally depends on the wall - its quality, material, and overall condition. Plus, there are several other considerations to keep in mind when deciding to use primer paints. 

So, before you jump onto the decision right away, here’s everything you should know about what does a primer do, when to use primer paint, and when to avoid using it. 

What Is a Primer Paint?

According to Wikipedia, “a primer or a base coat is a preparatory coating put on materials before painting”. 

Think of primer as an undercoat paint that creates the foundation for an unblemished paint job. No matter what your skill level, applying a primer before paint will help you achieve a flawless, professional-looking finish. 

A primer constituents solvents, resins, and some additive agents. It may also contain polyethene sometimes. 

Primer vs. Paint: What’s The Difference?

Primer and paint differ in their composition and purpose. Primers have a different chemical formulation of pigments and resins than regular paint. They use an adhesive resin to smoothen the wall surface. On the other hand, the pigmentation formula in paint allows different colours onto the wall surface. 

The primer seals the surface by penetrating it and ensures better adhesion, a smooth and stable foundation, and a better coating. On the contrary, paints hide the surface behind colours and add shine to it.

Types Of Primer Paints

Just like paint, different types of primer are available for different painting films. To be able to choose the most appropriate primer, you should know their distinctive features:


    • Stain Blocking Primer

This type of primer keeps your plaster wall blemish-free and smudge-free. Two types of stain-blocking primers are available for the interior, and exterior wall paints, including:

(i) Water-based: uses acrylic resins for the foundation. Contains solvent-based coverage of grease, scuff marks, etc. These are quick at drying and have a brilliant opacity. This type of primer has lower VOC levels which makes them less harmful.

(ii) Oil-based: ideal for a sleek surface with a glossy finish. It covers the pre-existing damage on walls caused by smoke, rust etc. Hence, great for getting rid of blemishes and stains and preventing them in the future. These work best with oil-based paints, making them very versatile. One can use it for various surfaces, such as steel, wood, and metal. 


    • Coloured Primer

Primers come in different accent colours as well. Your wall’s under-toned colour primers allow for vibrant colours. This allows for fewer top coatings. 


    • Drywall Primer

This primer type mainly contains polyvinyl acetate (PVA). It is ideal for porous surfaces and fills the ridges to prepare the wall for top coating.

What Does Primer Do?

The primer keeps the wall paint looking new for longer, offers better protection to the wall from wear and tear, and enables stronger adhesion between painted surfaces. 

Priming is the foundation of an excellent painting job. It creates a strong sticky surface enabling topcoats to bond well to it. If you have an existing painted wall that is rubbed down, priming can make it refurbish it. 

Primer is also significant when painting porous walls made of wood and concrete. It also helps hide joints, cover knots and wood grain, and stop previous colours from bleeding through. Above all, it reduces the need for additional finishing coats. 

Primer acts as a seal for non-water-resistant wall paints and aids in mould build-up. Further, if you have dirty paint surfaces that can’t be cleaned, priming can help. Primer will provide a base for the new paint to easily go on. 

If you have walls painted in dark colours, priming can turn the surface white without complexity. Applying a primer similar to the final colour to use on the top can help.

From reducing the number of coats to protecting your wall paint for years, a primer can do wonders for your home painting project. It can make your painting job easier in the long run. Commercial painters Melbourne give a quick answer to your question, what does primer do? 


    • Helps prevent stains and odours
    • Helps seal pores in unpainted surfaces like wood and drywall 
    • Prepares a surface for the paint to stick to 
    • Helps cover imperfections like patches on walls
    • Brings the paint colour to neutral for new paint coatings
    • Helps optimise the surface 

When To Use Primer Paint?

With a host of benefits that priming offers, is it ideal for every wall paint project? Actually, no! Priming is not suitable for all conditions. You may use the primer if you encounter any of the following situations: 

    • Unpainted wall or drywall

Such surfaces are quite absorbent, leading the paint coat to vanish quickly. Thus, you may end up putting multiple coats till you get an evenly painted surface. Unfortunately, it's a waste of material, money and even time to paint an absorbent surface. 

Applying primer, however, can save you from waste by filling the pores and making the surface paint-ready. Primer is cost-effective. Once you’ve applied the primer on the drywall, you can paint it with just one or two coats of paint. 


    • Glossy or Oil-based Paints 

Have you heard this before, oil and water don’t mix? This holds true for paints as well. Applying latex or water-based paint doesn’t work as the new paint fails to stick to the glossy surface. Hence, you need to apply a primer to make it work. 


    • Stained Surface

Applying one or two coats of primer before painting spotted or stained surfaces can be significant. Using thicker primers such as Kilz Maz   Consider using thicker primers such as Kilz 2 or Kilz Max for these conditions.


    • Major Colour Changes

If you are switching to a new wall colour, painting over an existing one won’t give you the desired colour of the new topcoat. The old and the new colours will mix and give a combination of the two as the final outcome on the wall.  

However, using a primer will get the correct colour by turning the surface colour to neutral and making it ready for the new colour.  

The same applies when going from dark to light colours. Only applying multiple coats of light colour on a dark surface can get you the result. But again, it increases the waste of paint and money. Using a primer before you paint the wall can help cut down on your material and cost significantly. 


    • Over Unfinished Wood

Unfinished or bare wood is among the toughest materials to paint. Wood’s natural fibres absorb a lot of paint. Moreover, the variations in the wood grain can lead to an uneven finish. Priming before painting unfinished wood can get you the best results. 


When Not To Use Primer?

Using primer in the below situations is a complete waste: 


    • On walls that are perfectly clear and in good condition
    • Walls or surfaces already painted with a primer.
    • When re-painting a surface with similar colour

Wrapping Up

Whether you are constructing your new home or refurbishing your office, knowing what does primer do and when it is best to prime can be significant. It will not just make your project easier but will also save you time and money. Further, deciding on the right primer type for your walls and other surfaces can make your painting project successful. 

But if you have trouble deciding on primer paint, feel free to reach out to the painting company Melbourne at Victoria Master Painting Services. For all residential or commercial painting enquiries, call us on 0435 754 330.

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