Managing Mildew, Moss And Algae On Exterior Painted Surfaces

Green or black stains on your home's exterior are usually the result of mildew, moss, or algae growth due to moist conditions. A fresh coat of paint may cover these stains, but they will only return if you don't eliminate the underlying cause. The following tips can help you deal with moisture stains and repaint your home successfully.

Tip #1: Check the Siding

If the stains are on wood siding or trim, it's a smart idea to check for moisture rot before beginning any painting project. Gently probe the wood with the blunt tip of a flat edge screwdriver. If the wood is soft and easily penetrated by the screwdriver, it has begun to rot and will need to be replaced before you paint.

Tip #2: Fix Your Landscaping

Poor air circulation and shade are the primary causes of trapped moisture and mildew or algae stains. This is usually a result of nearby landscaping. Trim back trees and shrubs so they are not touching the house. You may want to consider thinning overhead trees to allow more sunlight in, which will help moisture dry out more quickly.

Tip #3: Get It Clean

Before you start to paint, make sure all mildew, moss and algae is dead so it doesn't simply grow back. Mix up a diluted solution of bleach and water and scrub down the exterior walls with this where ever stains are visible – the bleach will kill the spores. When you are done, rinse thoroughly with clear water and allow it to dry out completely before you repaint.

Tip #4: Use a Primer

An exterior primer that contains mildew-resistant properties is another key to preventing it from growing back. This primer will cover any stains left over from the mildew or algae growth so they won't bleed through the new coats of paint. Apply a coat, let it dry, and then apply at least two coats of a quality exterior paint.

Tip #5: Keep It Clean

The final key to preventing regrowth is to monitor your home's exterior. Wash the siding every spring as part of your normal spring cleaning regimen. You can use a power washer set to low pressure or a simple sponge with soap and water. If you notice the beginning of mildew growth, quickly wash the area with your bleach solution or use a cleaner that specifically formulated to kill mildew, moss and algae on exterior painted surfaces.

To avoid these types of problems in the first place, contact a contractor, such as Octavio's Painting, LLC, for information on repainting your home or repairing existing damage professionally.   

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