Mold Keeps Growing In Your Screened Back Porch? Here’s Why

Every time you look around, mold pops up on your screened back porch. You do all you can to keep the room dry, but mold stills grows. One of the things about mold is that it can grow in almost any place as long as there's a water source available, such as dew or  evaporated water. Here's how dew and evaporated water causes mold and what you can do to stop them before they damage your screened back porch.

What's Dew and How Does It Affect Your Screened Back Porch?

Dew is a type of condensation that develops overnight when the temperatures outdoors drop. When it's hot outside, water evaporates into the air and becomes vapor. Once the temperatures drop at night, the vapor turns back into water. Small drops of water form on your grass, plants and outdoor chairs. But dew can also develop on the screens of your back porch and attract mold spores. Here's where you run into problems. 

The aluminum or steel surfaces of your screens become hot during the day because they attract the sun's heat. When it cools down at night, the cold air circulates over the screens and leaves behind water droplets or dew. 

Mold spores use air to get around. As they land on your wet screens, the spores consume the nutrients in the water and grow. Once it cools down outside, the dew evaporates. But mold spores don't just go away once the dew dries up. The evaporated dew circulating in your porch's indoor air protects the spores until the temperatures become cold enough to condensate again at night. 

The spores traveling through your porch's air seek new places to grow. For example, mold spores can show up in the smallest areas on your porch, such as small nooks or recesses. Your problem goes from bad to worse when mold penetrates the wooden material of the posts and frames of your porch. The spores and moisture weaken the wood from the inside out, which places your porch at risk for falling down or collapsing. 

If mold spreads to the ceiling of the porch, the wooden boards that support the roof can eventually rot and cave-in, especially if it rains a lot in your area. Heavy rainwater weakens and damages the roof even further.

Until you take steps to keep dew from forming on your screens, the mold will keep growing on your porch.

What Can You Do About the Dew on Your Screens?

Removing the dew from your screens every morning with a towel isn't enough to prevent mold growth and potential water damage in your porch, since mold also needs heat and humid air to grow. One of the things you can do is dehumidify your porch. If the weather's very hot and humid during the day, the porch can harbor or hold on to these conditions until late into the evening or night. You want to reduce the effects of heat and humidity on your porch all day long.

Also, place a circulating fan on the porch instead of just using your ceiling fan. Position the fan so that it blows against the outdoor air. The fan's backward position redirects or blocks most of the hot air outside of the porch, which reduces the humidity in the room.

You can also spray a natural disinfectant solution on your screens to keep mold growth down. Simply place 1/2 bottle of white vinegar in a spray bottle filled with water, then spray down the screens every morning or night. Vinegar destroys over 80 percent of mold spores, which greatly reduces your mold problem.

If you have moisture damage in the wooden frames and posts on your porch, replace them right away. If the entire porch shows signs of moisture damage, contact a mold prevention company for services. Leaving the damaged wood in place creates more problems for you, because the mold on them can spread to the rest of your home.