Across the United States each summer millions of home owners watch in horror as organic materials such as algae, mold, lichen and moss make their home amidst the shingle edges of their roofs. Such growth is most common in areas with warm and humid summers, particularly throughout the southeastern U.S., including Miami. The effects of these growing colonies look terrible and can harm the integrity of your South Florida roofing system by trapping water around the shingle edges, leading to increased deterioration and a shorter roof life.
Moss, in particular, is damaging because its roots actually get under the shingle, not only trapping moisture, but propping up edges and allowing moisture to penetrate to the wood, causing rot beneath as well. Removing it and preventing future growth is paramount in maintaining an effective, long lasting and attractive home.
Removing Organic Growth
Organic, living colonies of algae, mold, lichen and moss require little to sustain them; they need only humidity, warmth and a crevice of some sort in which to grab a foothold. Along the edges of various roofing materials, including asphalt, clay, ceramic and wood, exists the perfect, cozy spot for these organics to grow – this makes your roof an attractive place to put down roots. Once there, these colonies trap rainwater and dirt, holding them against your shingles, causing unsightly stains and potential damage. The good news is, removing and preventing it is relatively easy.
Removing moss is fairly simple, just use a firm bristled brush to push down the slope of your roof, forcing the moss’ short root system to dislodge and pushing the it off. Be sure to never sweep up the roof, as this could dislodge the shingle.
To remove algae, lichen and mold it is necessary to wash the roof with a cleaning solution. While many people use a mixture of bleach and water, and this is effective, it can also remove the color from your roofing material and damage vegetation around the building. Using an actual roof cleaning product is the best choice; to clean most effectively choose a somewhat overcast, cool day. Then, simply spray the cleaner all over the growing areas, allowing it to sit for about 20 minutes. Lightly scrub the surface, removing any traces. Finally, rinse with clean water or more cleanser.
Preventing Future Problems
Preventing future problems is relatively easy as well, though it requires a bit more skill. The best way to prevent organic growth is to introduce metal; materials such as zinc and copper inhibit mold, moss, lichen and algae. A good way to do this is to purchase copper or zinc flashing, and then install strips along the shingle edges, particularly along the roofs peak or as flashing along the chimney. When it rains, metal particles will flow downward, inhibiting further unwanted development.
Once you have removed all organic growth inspect your tile or shingle to ensure that they are well intact and in good condition. If the moss was very heavy or there for a long time some material may lose their granules and require replacement. Remember also that cleaning up there can be quite dangerous, as wet algae can be as slippery as ice. If you are at all uncomfortable with walking on your roof, contact a roofing professional to do the cleaning. They can do a comprehensive inspection for any damage caused by these substances, and make repairs before the damage becomes worse.