The sight of it may alarm you, but mold growth on pool screen enclosures is common. Mold grows outdoors in damp, shady areas, making your enclosure a prime breeding ground. Fortunately, killing mold is quite simple when you use household bleach, then follow up with a good, thorough scrubbing. If you use bleach for other cleaning jobs, you know to keep in mind a basic principle: Bleach is strong, so you don't need much for it to be effective.
Put on a face mask to cover your nose and mouth, eye goggles and gloves – precautions recommended by the U.S. Environmental Protection Agency so that you do not inhale or otherwise come into direct contact with mold spores. Scrape as much mold as you can from the screen with a wooden paint stirrer or something you can throw away. Put the residue and tool in a plastic bag and throw them out.
Mix a 80-20 ratio of water and bleach in a bucket. Consider this a light bleach solution and a good way to attack the mold growth on your screen enclosure. If the mold grows back or grows back quickly, increase the proportion of bleach to about 40 and then 50 percent.
Put on rubber gloves to protect your hands from a potential bleach irritation. Dip a soft-bristle brush into the bleach solution and scrub the screen enclosure up and down and from side to side. Don't forget to scrub the other side of the enclosure. Use a long-arm brush for tall or hard-to-reach areas of the enclosure.
Rinse off the bleach with a hose or pump sprayer. You might be tempted to use a pressure washer, but the force of the water could damage your screen enclosure. So err on the side of caution. Allow the enclosure to dry.
Combine mild dish soap and water in a bucket. Wash the enclosure with the soft bristle brush. Then rinse it thoroughly with water and allow it to dry.