The secret behind a flawless paint finish not only lies in the use of high-quality paint; in fact, the processes involved in the preparation stage play an essential role here. For a long-lasting paint result, preparing the surface is a crucial step, and there are several product options for different conditions.

When you get your house in Sydney painted by expert residential painters, primer, sealer and undercoat are the three most commonly used terms you will often hear in the surface preparation step. Whether you are giving your space a DIY painting makeover or getting service from a skilled house painter in Sydney, knowing the correct use of these products is a necessity to improve the longevity of the painted walls.


Are you wondering what is a primer used for? While mainly used as a first layer, primers are applied directly to surfaces. Primers have different ingredients, including binders that help in adhesion. Picking a primer paint with binders can prevent moisture from soaking into the substrate. If the wall is prone to mould and fungus, some specific primers contain properties that can prevent it. Also another purpose of primer is to stop rust from occurring on metal surfaces. The main difference between primer and other base layers is that it is used on new surfaces and works as its protector.


A paint sealer is a special coating that seals a surface before adding the final topcoat. Unlike primer, a sealer is mainly used for sealing the surface, not creating a paint base. It is used on-

  • Porous surfaces like concrete or brick
  • Previously stained or painted walls
  • Surfaces prone to bleeding

The primary purpose of using sealer in these bases is to create a barrier to stop the topcoat from soaking in. Also, it is used on stained walls so that the previously painted colour cannot bleed through the topcoat and ruin the finishing look. Depending on the substrate condition, it can be used along with primer or undercoat to make the coating process more effective.


An undercoat is also a base layer like a primer, but it is usually applied in the next step. The main difference with primer is that undercoat is mostly used in previously painted walls to hide scratches or imperfections. It is used to smooth out small bumps and provide an even surface for the topcoat. Additionally, an undercoat can lighten up a surface, especially when going from a dark to a light colour.

The main difference between primer, sealer, and undercoat is that primers are applied to unpainted surfaces. In contrast, sealers are mainly used as a primer substitute or applied before the primer. But an undercoat is used after primer, mainly on a surface already coated with paint. Each of these products has a purpose to serve and is definitely not interchangeable.

It is pretty normal to get confused while choosing the right one for your property, so getting help from professional painters in Sydney is the wisest decision. Among painting services in Sydney, Priority One Coatings can help you out with its 32+ years of experience in this industry. Our house painters use the right products in surface preparation and create a smooth base regardless of the condition of your home.
So, call us today and give your residence the best painting makeover it deserves.

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