Is Paint Sealer Necessary? 

 July 3, 2022

By  Dale Keese

Painting is a common home improvement project that can increase the value of your home. Aside from paint, experts recommend the use of sealers for a successful paint job, but is it really necessary?

Sealers are necessary to prep porous surfaces and ensure that the paint bonds with the surface. It’s especially important if the surface contains cracks, holes, stains, is chalky, or has never been painted. Sealing before painting is also necessary for masonry surfaces.

There are other things to know about using paint sealer. Read on below to learn more.

Is It Necessary To Use a Paint Sealer?

Proper application is always critical for a successful paint job.

Experts have always recommended the use of sealer as a primer before applying paint because it’s a necessary step for protecting both the paint job and the wall. The primary purpose of sealing is to make porous surfaces non-porous so that air and liquids don’t penetrate, thus ruining the aesthetic and eventually, degrade the surface quality.

Aside from that, there are other reasons why using a paint sealer is necessary.

Sealing Holes and Cracks in Walls

Applying regular paint directly onto holes and cracks especially on old walls won’t be sufficient for covering it. On the other hand, a sealer is formulated for covering these blemishes as long as it’s applied before paint. Once the cracks and holes have been properly covered, paint will go on smoothly after sealer application.

Flaked Surfaces

Flaky walls have an uneven surface. If paint is applied directly to the flaky areas, it will have the same result only with the painted color, leaving you with an eyesore. Sealing this area first will help even out the flakiness to ensure an even painting application.

Chalky Walls

Chalky walls have a powdery surface which prevents the pain from bonding to the wall. Sealing will create an intermediary surface between the wall and the paint, resulting in a sticky surface that the paint can adhere to. Additionally, paint won’t peel off from the sealed surface.

Stained Walls

Painting over stained walls will not be enough to cover it up. Sealers are formulated to cover up the pain efficiently, leaving you with a clean surface for applying paint.

Painting Over Dark Paint

Sealing a wall that has been previously painted with dark paint is more efficient and affordable compared to covering it up with normal paint. You would need a significantly larger amount of regular paint to cover a dark color, whereas it would only require one or two coats of sealer.

Help Layers Bond

Sealers are formulated with natural bonding agents that stick to the surface of walls efficiently. Once sealer has been applied on walls, paint can bond with the sealer surface preventing peeling and flaking later on.

Preserve Paint Quality

Overall, sealing surfaces before painting is essential for preserving the quality of the paint. In some cases, such as painting over old walls, the paint will become chalky and damp when it reacts with the dried paint. Sealers prevent this from happening and increase the chances of a paint job done well.

Surfaces That Require Sealing Before Painting

Aside from interior or exterior walls, these are other surface types that require sealing before painting:

  • Old, unpainted wood
  • Painted wood
  • New unpainted wood
  • Masonry including concrete, cinder block, unglazed brick
  • Any unpainted surface including drywall, plaster, and old wood
  • Bare wood and open-grained wood, especially those that tend to bleed through paint
  • Ferrous metals
  • Aluminum and galvanized iron


Sealing is necessary before painting over numerous home improvement projects. Don’t skip this step to avoid costly and time-consuming problems down the road.

About the author

Hey, I'm Dale Keese.. thanks for reading.. hopefully this article can save you some time and trouble with your sealing job. I'm also in the process of making some video walk-throughs for youtube so check back soon! thanks

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