Mildew on the Interior Walls - Can You Paint Over it?

Mildew. Just the word alone can strike fear into the hearts of homeowners everywhere. But mildew doesn’t have to be scary. In fact, with a little bit of elbow grease (and the right kind of paint), you can turn that mildew into an opportunity to fix some problems in your house. Furthermore, this problem is now your excuse for a brand new, interior painting job. Let’s look into what mildew is and what we can do about it when it’s time to paint.

What is Mildew?

Mildew is a fungi that thrives in warm, damp environments. It can be found outdoors, on surfaces like decks, patios, and outdoor furniture. Left unchecked, mildew can cause damage to the outside of your house. When mildew is indoors it can cause respiratory issues, headaches and sinus congestion.

Look for it in the bathrooms and the kitchen where humidity levels are high but you can also find mildew:

  • On window sills where there is condensation
  • Around indoor plants
  • In the basement
  • In the attic
  • On walls behind furniture
  • In the garage

After identifying it, with a little bit of effort, and some prevention tips, you can rid your home of mildew for good.

Is it Mould or Mildew?

It can be difficult to tell the difference between these two common types of fungi, but there are a few key distinctions. Mildew is actually one type of mould and it is less harmful than the black growth it usually gets mixed up with. Both mould and mildew thrive in dark and damp environments and can be found on walls, ceilings, or surfaces that haven’t been cleaned or ventilated. However, mould is usually darker in colour, while mildew tends to look lighter and grey. Mould also has a fuzzy appearance, while mildew is usually smooth. 

In terms of health implications, both mould and mildew can cause similar respiratory problems and allergic reactions. However, mould is generally considered more harmful, as it can produce toxins that potentially cause more serious health problems. It is equally important to take steps to prevent both mould and mildew from taking hold in your home. Here is a good resource fom EPA, get a quick glimpse of some of the most important ways to protect your home from mold by touring the Mold House

Preventing Mildew Growth in the First Place

Mildew is a type of fungus that thrives in humid environments. To prevent its growth in your home, it’s important to keep the humidity levels low. This can be done by opening windows and using fans, dehumidifiers, and air conditioners. You should also make sure to use the bathroom and kitchen exhaust fans when showering or cooking. And if you have a humidifier, be sure to empty and clean it regularly. If you live in a humid climate, it’s important to take all these precautions to keep your home mildew free.

How to Clean Mildew Before Painting

Mix 3 Parts Water with 1 Part Bleach
then Scrub & Rinse
3 Parts Water – 1 Part Bleach – Scrub & Rinse

If you are planning to paint a room that has mildew, it’s important to clean the affected surfaces. Painting over mildew will not make it go away, in fact, it will be more difficult to clean mildew in the future when the mildew grows under the new paint.

The best way to clean mildew is by using a water and bleach solution. Mix three parts of water with one part bleach, and apply it to the affected surface with a sponge or brush. Scrub well, then rinse with clean water. You may need to repeat the process several times to completely clean the mildew. Once the surface is washed and rinsed, be sure to allow it to dry completely before painting. If it’s taking too long to dry, use a fan to speed up the process.

What If the Mildew is Behind the Paint?

If your home has an extensive infestation of mildew, it just might not just be a surface problem. Sometimes it’s behind the old paint, maybe behind the wallpaper, but definitely inside the drywall. Painting over the affected area is just a temporary cosmetic fix but it will be more difficult to deal with it in the future. You need to cut out the infected part of the wall and replace it with new drywall. This is a time consuming process and requires some skill but it’s the only way to  remove every trace of the mildew. 

Now that you have an opportunity to see what is behind the wall, it might be possible to find the source of the problem. If you identify the culprit of the moisture, this is the time to address it and fix the problem forever. After removing the problem and installing a new section of drywall, you can be confident that mildew will not appear here again. 

Mildew Resistant Paints and Products

Anti mildew paints

First of all, oil based paints are the worst because they contain organic elements such as resins. These ingredients are a food source for the mildew fungi. Because of environmental restrictions, very few oil based paints are used today, so let’s talk about water based acrylic paints.

The best quality acrylic paints protect surfaces by creating a moisture barrier with their film. In addition to this, the best quality paints contain certain fungicides that kill mildew. You can purchase mildewcides and add it to the paint or use top quality paints that are made specifically for that purpose. Here are some of our favourites:

  • PERMA-WHITE Mould & Mildew-Proof Interior Paint by RUST-OLEUM. This was our go to coating years ago and still get good results. Here is some information about it.
  • Benjamin Moore Aura, which in our opinion is the best interior paint.
  • Benjamin Moore Bath & Spa, specifically formulated to resist moisture in bathrooms. We used this paint extensively, even in humid commercial spas and we absolutely recommend it.

In Conclusion:

Mildew can be a pesky problem, but it’s one that you can easily take care of with a little elbow grease and the right paints. Our team of professional painters are equipped with the knowledge and tools to take on any mildew-covered surface. We’ll do the prep work for you and use paints that are mildew resistant, so your paint job will stay looking great for years to come. Ready to get started? Give us a call today!

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