Dockside fabric awnings, boat covers, and boat lift canopies are built to protect boats, marine craft, houses, docks, and even people from extreme environments found near large bodies of water. Typically, these shade structures are made using commercial-grade PVC composite textiles that are highly durable and resistant to both UV and mildew. Specifically, fabrics like Herculite’s Patio 500 and Coastline Plus are popular PVC textiles for this application as they contain flame-resistant and mildew inhibitors integrated in the raw materials and composite formulation. These inhibitor chemicals are inherent and will not degrade or “wash out” during the life of the textile.
Airborne red tides and algae spores present a unique challenge for canopy owners regarding the cleaning and maintenance of protective fabrics. Commonly known as “red tides,” scientists refer to these as harmful algal blooms, or HABs. These incidents occur through the explosive growth of ocean algae, usually caused by an unnatural increase in dissolved nutrients in seawater. As the algae populations explode, their blooming turns the ocean water red, thus the colloquial name of “red tide.”
These blooms and subsequent airborne releases occur in places like Florida with a seasonal frequency, but less frequently in other areas when certain conditions arise. Impacts can sometimes be minimal, but a large toxic bloom can disrupt the ecosystem, human health, and local economy. Scientists at the National Oceanic and Atmospheric Administration (NOAA) have developed a harmful aquatic bacteria forecasting system: https://coastalscience.noaa.gov/science-areas/stressor-impacts-mitigation/hab-forecasts/ for specific regions of the United States where these can be common, including Florida, California, and Lake Erie.
Most scientific studies on the effects of harmful algae blooms have been focused on the potential causes and the blooms’ impact on human health and the environment. However, there may be some effects on property and materials close to the body of water affected. Any fabric or material that has contact with the airborne bloom for an extended period could be at risk of damage if not maintained.
While Herculite fabrics like Patio 500 and Coastline Plus do offer mold and mildew resistance, red tide airborne blooms can result in such extreme levels of organic materials in the air that they accumulate to the levels where contaminants, like mold and mildew, can survive on that buildup. When this happens, the aggressive spores gather and act as a barrier between the mildew inhibitors and the mildew itself, becoming the “carrier” of the mildew. The red tide algae spores create a food source on the fabric surface to grow mildew, bypassing the inherent fabric’s resistance. The results can be ugly, with swirls of mold and mildew developing over time that can be difficult to clean.
Herculite's Coastline Plus awning fabrics feature RainKleen®, a top surface coating technology that serves as a barrier between the fabric surface and harmful environmental elements, including airborne particles. RainKleen’s proprietary surface coating can reduce damage caused by Harmful Airborne Particles (HABs) containing blue-green algae and red-tide particles in the form of cyanobacteria.
We recommend that shade structures in mildew-prone areas, made with Patio 500 or Coastline Plus, are adequately maintained on a cleaning schedule. Increasing the frequency of cleaning during summer months and red tide “season” will help prevent contaminant buildup and will help to allow the fabrics' antifungal and stain-prevention attributes to function normally. Specifically, we recommend frequent hosing with clear water to prevent dirt accumulation. Maintenance cleaning can be accomplished by applying 50/50 strength bleach/water and using an extension, brushing softly to cover thoroughly the surface area. Allow the bleach solution to remain on the surface for two or three minutes, then thoroughly rinse (very thoroughly) with clear water. It’s very important to protect the surrounding area (furnishings, plants, and vegetation) that the bleach might damage.
For more information on the importance of fabric maintenance, specific types of fabric cleaning, and a general overview on the importance of regular fabric cleaning, visit our post “how to clean fabrics.”
For more information on red tides or harmful algae blooms visit the National Oceanic and Atmospheric Administration’s website here: https://oceanservice.noaa.gov/hazards/hab/.