Moisture Causes Painting Mayhem!

Moisture will wreak havoc on your home.  The most immediate effect of an excess moisture problem is the formation of mildew.  One of the major causes of exterior paint failure is simply painting over mildew.  It sounds simple but this happens much more often than you might realize.Taking steps to eliminate mildew growth and control moisture before painting are measures which will save you money by preventing damage to your home and furnishings.

It’s also important to get rid of mildew before painting for health reasons. According to the U.S. Centers for Disease Control and Prevention (CDC), mildew is a serious health hazard that will cause respiratory problems, particularly for people with asthma. Individuals with compromised immune systems are susceptible to respiratory and lung infections as a result of mildew exposure.

Mildew often looks very similar to dirt. Sometimes it is brown, black, or green in appearance; it can also appear powdery, slimy, or fuzzy. Mildew is a fungus which eats through porous painted walls and other surfaces. The paint is destroyed as mildew eats its way through the sheetrock, masonry or wood.


If you are unsure whether there is mildew in your home, there is a simple bleach test that you can use. Simply scrub a small amount of household bleach on the area in question.  If it is mildew, the stain will be removed within a couple of minutes. If it is dirt, the bleach will have no effect.


The reason people sometimes apply paint on top of mildew is because they are either unaware of the potential future consequences or they are simply seeking a quick fix. Mildew will bleed through the paint eventually. Although some paints contain mildew inhibitors, these products merely inhibit new mildew from growing. They do not destroy mold that already exists.


The best approach is to first destroy the mildew and then paint. Wear eye protection and rubber gloves to apply a solution of three quarts water to one quart bleach to the area with signs of mildew. The mildewed area can be disinfected using a sponge or a garden sprayer. After allowing it to soak in for 20 minutes, rinse with water. Warning: No other product with ammonia or household cleaner should be added because toxic gases are released when ammonia is mixed with chlorine bleach.


It’s possible that chlorine bleach could damage mildewed surfaces that are aluminum, plastic, or chipped enamel; do a small test area with the solution first.


After the mildew has been removed, it’s safe to paint. You can stop the reappearance of mildew growth by using paint with mildew inhibitor. When selecting a type of paint to use, keep the following information in mind:


  • Paint that contains linseed oils is extremely vulnerable to mildew.
  • Lower grade paints contain thickeners which have been known to feed mold and promote its growth.
  • Paint that is mixed with zinc oxide is more resistant to mildew than paint with titanium dioxide.


Contact us today for help choosing interior or exterior paint with mildew inhibitors.

Welcome Video

Contact Us

MDF Painting & Power Washing, LLC
  • 500 W Putnam Ave, Ste 400a
    Greenwich, CT 06830
  • 203-542-9547

Google Reviews

Request an Estimate

Get Your Free Guide!