4 Coats of Paint and Still Patchy – What’s Wrong with the Project?

Paintjobs are usually fun and give you a sense of achievement, especially if you are a DIYer. However, there are so many things that can go wrong while painting, and this can make you feel frustrated. Even after investing in paint, rollers, and overalls, among other things, you can still get patches on your project.

Today, we discuss a problem that has affected almost every DIYer and professional painter at one point or another. Patches on a paint project will leave you annoyed, lost, and or even embarrassed. The one thing that you shouldn’t feel is incompetent because you can correct this. Yes, money and time are lost, but we will explain why the patches appeared even after 4 coats of paint.

Why are there patches even after four coats?

It doesn’t matter the type of paint you are using; if done wrong, you might live to regret ever undertaking the project. A paint job requires that you thoroughly prepare before you can commence. You must also invest in the right gear and allocate enough time if exceptional results are to be witnessed.

After seeing patches on their projects, whether walls, tables, or dressers, many people will apply another coat of paint. They apply another coat hoping the patch will disappear. And behold, the patch remains or becomes even more prominent. You can apply as many coats as four or even five, and the patch still remains stubborn. Here are the possible causes of this problem;

1) Job poorly done / inexperience

When you see a patch on a project, the first thing that comes to mind is likely, the person who painted is not good at painting or is inexperienced. In most cases, this is precisely the case. Painting is unlike many menial jobs out there. You must have an eye for art which helps you balance your hand as you paint. You will often find the right materials and paint were bought. The project is sanded or prepared as required, but the painter is the weak link.


The solution to this problem is to invest in a little paint education. Not necessarily in a class, but you can have someone coach you. Many paint cans have easy-to-follow instructions, though. Ignoring simple tips such as diluting ratio will ultimately lead to poor results and, in many instances, patches.

2) Poor choice of paint

Using the wrong paint on a project can lead to a lot of issues, among them patches. Sometimes, you might pick cheap paint that is unsuitable for the surface they are painting. The wrong paint lacks consistency, and patches will be scattered throughout the project. In some cases, the paint you use might not be compatible with the surface you are working on.


You have to ensure you buy the right paint. There is paint for metal surfaces and one for wooden surfaces. Ask the paint shop assistant for advice, and also do some research before dipping that roller in the paint jar. But as they say, you get what you pay. This is especially true where paint is concerned.

3) Poor plastering

All aspects of the job must be done right for the best result in painting. You might have high-quality paint, the right roller, and the proper undercoat. But you might have forgotten all about the importance of good plastering. When plastering is not done right, you will likely end up with patches all over the ceiling or walls you are working on. The little bumps on the wall create shadows that give a patchy look.


No matter the layers you paint a poorly plastered surface, the patches will always remain. The solution to this problem is to use polyfilla and fill all cracks and gaps. You can use a good undercoat to cover most of the defects on the surface. Once you are satisfied with the outcome the undercoat has given you, you can paint.

4) Flashing

Flashing is when light from multiple different directions hits a surface. This happens mostly on corridor walls. When light from the doorway and different windows hit a wall, you might realize there is a patch or patches on it.


A lot of people just learn to adapt to this annoying phenomenon. However, investing in a matt will help you solve this issue for good. A matt paint will solve the flashing problem in high-traffic places such as hallways, kitchens, and family rooms.

5) The surface not cleaned

As obvious and straightforward as this step might seem, many people will skip cleaning the surface they intend to paint. The results can be annoying, to say the least. Surfaces will have dirt, grime, grease, or old peeling paint, especially if not cleaned recently.


Use water, soap, and a duster to clean away all the surfaces you intend to paint. Let the surface dry before you can start the paint job.

6) Failing to apply primer

Primer is a base coat applied on a surface to help treat it before applying the main coat. Primer enhances optimal adhesion hence making the paint last longer and avoiding patches. Moreover, the primer layer acts as a sealer on porous surfaces such as walls and ceilings, meaning you won’t need many coats of paint. When you don’t apply primer, the surface can absorb more paint in some sections, and others will be okay. This leaves the surface with patches where the paint is well done and others without.


It is advisable always to use a primer before you apply paint on a surface. The primer should be on the entire surface and not sections. It is critical to use primer on all old jobs.

7) Wrong sealer

There are paint jobs that require the use of a sealer. In certain projects, there is the risk of your paint soaking onto the substrate, no matter the number of layers applied. A paint sealer helps prevent paint from soaking onto the surface. In some way, it creates a water-resistant layer between the surface and the top layers of your paint but still prevents the topcoat from peeling off. While skipping a sealer coat will likely lead to patches on your project, picking the wrong sealer can lead to the same bad results. A sealer can be used with or in place of a primer.


Read the instructions on the sealer container to ensure you pick the right sealer for your paint and surface.

Difference between primer, undercoat, and sealer

As pointed out earlier;

  • Primer is the first coat of paint on a rough surface. Primer is essential because it smooths patches on a surface. It prevents rust on a metal surface and blocks out stains. Primer will also prevent mold and fungus from forming and prevent moisture from getting between the substrate and the topcoat.
  • On the other hand, the sealer is a special primer specifically designed to prevent the topcoat from soaking onto the substrate. A sealer can be used together with primer or in place of a primer.
  • An undercoat is crucial in preventing patches on your project. It is applied after a primer and will fill all minor imperfections and create a smooth surface that has an even color. An undercoat will lighten the surface, especially if you are looking to change a dark undercover into a pale color.

What to do to avoid patches on your paint project

There are simple steps you can follow to avoid a repeat of patches on your project. Of course, if the patches are too bad, you may need to remove the entire paint. However, to prevent this in the first place, here are some simple tips to follow;

  1. Measure the project’s surface area – Measuring the surface area helps determine how much paint will be needed. This prevents you from spreading the paint too thin in some places. Basically, a liter of paint should cover at least 10 sq m.
  2. Get the color right – Different types of surfaces require different types of paint and colors. It is imperative you get a sample to help you see how the color reacts to light and the substrate first. The kitchen might need a different type of finish from that of a bedroom.
  3. Get the right tools – As earlier noted, using the wrong tools can lead to patches on your project. Don’t overlook even the simple tools and materials. Invest in a painting tray, painter’s masking tape, water and soap, rollers, and brushes.
  4. Prep the surface – Prep the surface by cleaning the removing all objects that might distract you. Small things like pebbles can trip you, and you may splash paint all over yourself or on surfaces not targeted. Don’t overlook the importance of cleaning the surface before starting to paint. In fact, consider cleaning the surface with water and soap and leaving it to dry as a must-step.


A good paint job requires skill. However, that skill is patience and following instructions. To get the best results, never rush while painting. Don’t rush the drying of the undercoat or the first coat. Don’t skip a grit while sanding the surface. All these seemingly small things are the ones that often leave you with a patchy project. Finally, paint in natural light.