Treating Algae and Moss in Hawaii

How to Treat and kill moss and mold in Hawaii

Bleach: Mix equal parts water and bleach to kill algae. Spray it on the area, let it sit for 15-20 minutes, then rinse well. Use safety gear and protect nearby plants since it’s strong.

Pool shock: Raises chlorine levels in pools, killing algae, bacteria, and other germs. Available as granules to mix with water or as ready-to-use liquid.

Pool filter: Traps dirt and helps keep the water clean. A dirty filter can lead to cloudy or contaminated water.

Phosphate remover: Takes out phosphates, which feed algae. These can come from fertilizer runoff or fallen leaves.

Pool water clarifier: Reduces algae and clears up pool water.

Algae mildew cleaner: Cleans algae, mildew, and mold from different surfaces.

Understanding how to effectively address algae and moss growth on rooftops involves recognizing their distinct characteristics and corresponding growth patterns. Although algae and moss are sometimes mistaken for one another, they require different techniques for prevention and removal.

The dark streaks often seen on roofs in areas such as the United States and Canada are primarily caused by algae, rather than mold or mildew. Algae flourish in moisture-prone areas on roof surfaces, particularly in humid or coastal climates. The most prevalent type, known as gloeocapsa magma or blue-green algae, forms a dark pigmented sheath that shields it from ultraviolet rays. Initially, algae discoloration appears as small spots that rapidly develop into noticeable streaks. By the time these signs emerge, the algae may have been growing unnoticed for several months or longer.

To manage algae growth, it is essential to implement both preventative measures and effective removal techniques. Regular maintenance, such as cleaning gutters, trimming overhanging branches, and addressing areas prone to moisture, can greatly reduce the likelihood of algae growth. When tackling existing algae, a suitable cleaning solution specifically designed for roof algae can be applied, followed by a thorough rinse. Utilizing soft wash techniques helps ensure that the roof’s structural integrity remains intact while effectively eliminating the algae.

In contrast, moss thrives in shaded, damp environments and typically appears as soft, green patches. Unlike algae, moss can retain moisture against the roof's surface, leading to damage over time.

Algae spores can rapidly proliferate via wind or animals, leading to extensive growth in neighborhoods, particularly in apartment complexes, condominiums, and townhouses. While algae does not inflict direct damage on asphalt shingles, it certainly detracts from the appearance of roofs. For “cool” roofs, which are designed to reflect sunlight, algae can diminish their long-term performance, making it essential to tackle algae issues promptly.

Moss, being a non-vascular plant, absorbs water through its leaves and flourishes in damp conditions, especially on north-facing roofs with limited sunlight exposure. Overhanging trees contribute to moss growth by providing shade and dropping organic debris onto the roof. Moss spores spread in a manner similar to algae, but they pose a greater risk to asphalt shingles. The accumulation of moss can lift the leading edges of shingles, increasing the likelihood of shingle loss during high winds. Additionally, significant moss growth can cause water to move laterally, potentially leading to moisture damage in the roof deck or creating leaks.

To effectively clean algae and moss from a roof, a solution of equal parts laundry strength liquid chlorine bleach and water should be applied. Use a sprayer to apply the mixture and allow it to dwell on the roof for 15 to 20 minutes before rinsing thoroughly with low-pressure water. Extended dwell times may be necessary, but it is vital not to let the solution dry on the surface to ensure a proper rinse. It is also important to protect landscaping and surrounding areas from the bleach solution and to wear appropriate personal protective equipment during the process. Algae will naturally wash away with subsequent rainfall, while moss will gradually loosen and can be cleared away using a leaf blower. For severe moss issues, multiple treatments may be required. It is crucial to avoid using pressure washers on asphalt shingle roofs, as this can lead to granule loss and reduce the lifespan of the roof.