Do You Have to Paint Over Zinsser Mold Killing Primer

If your home has moldy areas, priming over them can certainly kill them off. While paint or multi-use primer isn’t designed to kill off mold, you can eliminate the fungus with Zinsser Mold Killing Primer, as a specialty primer.

However, many wonder if painting is even necessary at all after using the primer first. Do you have to paint over Zinsser Mold Killing Primer? 

In this post, we’ll answer this question and cover how to use this product in your house.


Yes, you have to paint over Zinsser Mold Killing Primer. As a primer, it is designed to be painted on, or it will crack and flake much more easily after application. Moreover, the primer isn’t nearly as effective for inhibiting mold and mildew growth without painting or sealing over it. 

Do you have to paint over Zinsser Mold Killing Primer?

Using primer as a paint or final topcoat is not recommended. Primers are only meant to prepare the surface for a paint coat, increasing adhesion and protecting it from stains, mold, mildew, and bleed-through.

So yes, you do have to paint over Zinsser Mold Killing Primer. In fact, it is necessary to use a paint or topcoat when using Zinsser Primer products.

Zinsser Mold Killing Primer, in itself, doesn’t offer enough protection on any surface, especially on porous objects like wood and textiles. Without a coat of paint on top, the tacky primer will accumulate dust and grime easily and will wear away relatively easily, especially on outdoor surfaces. 

How to apply Zinsser Mold Killing Primer

Zinsser Mold Killing Primer is one of the most popular mold and mildew inhibiting primers on the market, as it offers great coverage and is relatively easy to use. Let’s look at how to use this product below.

Step 1: Prepare tools and supplies

First, prepare all your tools and supplies before priming and painting. This streamlines the process and makes it easier to finish the job. To use the primer, you’ll need:

  • Zinsser Mold Killing Primer
  • High-quality brush or high-density roller

For protecting your floors and yourself:

  • Old tarps or drop cloths for the floor
  • Mask, goggles, and gloves (it’s a primer high in VOCs making a respiratory mask and other safety precautions necessary, especially in enclosed areas with poor airflow where you can breathe in the odors of the primer. A safety mask is also important to prevent breathing in mold spores in the infected area.)

Step 2: Prepare your surface

If your surface has considerable mold and mildew damage, clean it first. But before getting started, be sure to wear a respiratory mask, goggles, and gloves. Mold spores can be extremely harmful to your health when breathed in, and taking the proper safety precautions is a must. 

Mix a solution of mild dishwashing liquid and water in a small pail. Soak a rag in your solution and lightly wring it out to make sure it’s not sopping wet. Then, let the surface dry before moving on to the next step. You should only need to let the surface dry for a few hours depending on the airflow, temperature, and humidity of the area, but to be extra safe, let the surface dry overnight. 

If your surface has extreme mold damage, it is best to have this checked by professionals first, as it could mean you have severe water damage behind the area you’re painting. If you have severe water damage in that area, you may need the assistance of a plumber to fix any leakage. Mold treatment professionals will be needed to handle the mold itself. 

Step 3: Apply primer

Apply the primer once your surface is properly cleaned and dry.

Mix the primer thoroughly in the can with a stirring stick. Then, transfer the amount of primer you need for the project to a separate container into a separate can or pail.

Dip a high-quality brush or roller into the primer. Spread the primer onto the surface in long, even strokes. 

Let the primer dry for an hour. For severe mold problems, it’s best to apply a second coat to fortify the first coat, and ensure that the moldy area has been sealed in. 

Step 4: Add the paint and finish

Wait until the primer has sufficiently dried. In most cases, the primer will dry in less than an hour but in areas of high humidity and poor airflow, it may take slightly longer. After all, the Zinsser Mold Killing Primer dry-time is contingent on the environment you apply it. To be extra safe, wait at least an hour before moving on to next steps. 

Once the primer has sufficiently dried, add your first coat of paint. You can use either water or oil-based mediums over this product. For the best results, apply a second coat of paint after the first has sufficiently dried. 

When you should take extra measures…

Under some circumstances, your mold issue might be too extreme to fix with just mold-killing primer. If the problem has gotten to the point where thick black mold has become extremely prevalent and has consumed a large portion of a room or basement, mold removal might be necessary. Mold-killing primer is best suited for small traces of mold or mildew, but not copious amounts. 

Additionally, if your mold issue is extremely prevalent, this might be an indicator of severe water damage. Unfortunately, priming over areas of water damage might not make sense without addressing the source of the water damage first. If there is a leaky pipe that is creating water damage, it’s best to fix that pipe first before repairing the damage. Have the area inspected by a reputable plumber before moving on to next steps.



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