The exterior of your home is just as likely to be affected by mold and mildew as the interior of your home—perhaps even more so, because it usually encounters more mold spores and more moisture than the interior of your home is. Finding a spot of mold or the evidence of mildew on your home can be extremely annoying. At first blush, you might think it is just a little bit of dirt, but as soon as you start trying to scrub it away, it becomes obvious that you are dealing with something else entirely.
Where does mold and mildew come from? And how can you get rid of the problem before it is time to repaint your wall? Here is everything you need to know about mold and mildew and what to do if you notice it on your home’s exterior:
Mildew and Mold
Mildew can usually be identified by its growth pattern and by its consistency. It grows in a large, flat area, and will be downy or powdery. You’ll first see mildew with a powdery consistency that is white, turning to brown and then black over time. If your mildew is downy, it will first be yellow, and then become brown. You’ll probably start to notice mildew first on the north side of your home. This part of your house gets the least sunlight, so it stays wet and shaded—the perfect recipe for growing mildew.
Mold is most easily identified by its fuzzy appearance, and it comes in a wide variety of different colors, ranging from white, to yellow, green, blue, gray, brown, and black. Mold needs a wet surface to grow on, making it very common in humid parts of the country.
Neither mold nor mildew is caused by paint. Both of these outdoor pests will grow on anything wet that is constantly in the shade. All of us probably have at least one wall of our home that very rarely gets sun, simply because of how the home is positioned. Both mold and mildew are in the fungi family and once a colony begins, it can quickly spread.
What to Do
Most people think that they can kill a colony of mold or mildew by painting over it. While this may hide the colony for a little while, it will not actually kill it or solve the problem. It will keep coming back again and again, no matter how many times you paint over it. If you do not take care of the mildew problem before you paint, it is likely to grow straight through your new coat, and become an unsightly stain on the side of your house again.
If you notice the problem early, you may not even need to paint over the surface after removing the colony. Cleaning the area properly should remove the mildew or mold and make your home beautiful again.
Start by testing for mildew. This is fairly easy to do. Drop a little bit of common, everyday bleach onto the spot that you suspect is mildew, and wait for a moment. If the stain in the area where you have dropped the bleach totally disappears, you probably have a mildew infestation. If it does not disappear, it is much more likely to be dirt, which can be cleaned away with soap and water.
Lots of great paints actually contain a chemical which will kill mildew, if used correctly. A latex-based paint is more likely to resist the growth of mildew than a water-based one, as it repels water, rather than retains it. Oil-based paints can often contain nutrients that fuel a mildew colony, so they are usually not a good choice for homes prone to mildew, either.
Paints with a high gloss level have a finish that is more difficult for mildew and mold spores to grip on to, making it less likely that a colony will grow on glossy paint. Darker colors can also help to prevent mildew growth, as these attract heat and dry faster when they are wet, usually too quickly for a colony to attach and start to grow.
A solution of bleach and water, sprayed on to the colony, and then scrubbed with a stiff brush, can clear away these colonies. Following cleaning with a layer of mildew-resistant paint, chosen according to the criteria above, is a good way to make sure that you do not have to deal with an infestation again. Be on the lookout for mildew and mold, as the earlier you find it, the easier it is to remove and remediate.
