Your roof is probably the most important part of your home. It protects all other elements of the home from premature failure and having to be replaced. That is why it is so costly to replace. So, proper roof maintenance and inspections should be a normality for homeowners.

There are many reasons for cleaning a “dirty roof.” The most important reason being that your roof is not actually that dirty at all. It is, however, infested with billions of micro organisms known as Gloeocapsa Magma. This strain of bacteria is a highly aggressive mold that is causing all the black streaks and darkening on the roofs in Hawaii. It not only makes the roof look old and filthy, but it is also decomposing the roof and playing a major role in premature roof aging and failure.


This bacteria lays down an extensive filament root system that is known to cause cracking and fissures. As your roof heats up and cools down throughout the day, it expands and contracts. This allows these root systems to penetrate deeper and grow larger. It also makes for a very welcoming environment for larger strains of mold and bacteria such as lichens and algae. Mother Nature uses these molds and bacterias to decompose things and make larger objects smaller, eventually turning them to dirt. These molds and bacterias are actually feasting on the surfaces they dwell on.

Another important factor is that, as this food source is broken down through photo-synthesis, the by-product or waste that is excreted is highly acidic and also damaging to the roof. If not treated in a timely matter, these molds, mildews and bacterias will have a significant role in your roof’s premature failure, sometimes by as much as 30 percent of the expected life of the roofing material.

This is why many roofing material manufacturers are now adding algaecides and other mold prevention methods to products. However, because of the moist, humid environment that is found in Hawaii, no product will keep these elements away permanently. So it is critical that you learn your manufacturer’s warranty for mold and their recommendations for the cleaning of your specific roof. You would be wise to get references to customers they have done mold-related warranty work for in the past.

There are roofing companies out there that are realizing that the mold problem in Hawaii is worse than they anticipated, and are not honoring their warranties regarding mold. There are usually loop holes or clauses in the contracts that allow them to get out of this particular warranty work. Also, the roofing company that installs your roof is not always the best choice for cleaning the roof. Roof cleaning is a skilled trade and should not be done by those without the proper training and experience.


Most people are not aware that a pressure washer should not be used to clean a roof, as it is too aggressive and will cause extensive amounts of damage to your roof. In fact, ARMA (Asphalt Roofing Manufacturers of America) is very clear on its views of a pressure washer being used for roof cleaning, and that in most cases, it will void your roof warranty. Besides a voided warranty, a pressure washer does not resolve the problem. The roof will appear to be clean, but it does nothing for the eradication of the mold and bacteria that are causing the problems. It simply sheers the mold off at the surface, allowing it to grow back quicker, thicker and fuller — just like when you cut your grass.

Mike Wedge from Envirowash Hawaii LLC, Hawaii’s only SoftWash Systems certified roof and exterior soft wash company, said, “Because we know that this mold is a living organism, we know that a 100 percent kill rate is required to alleviate this problem. This is not a cleaning concern, but a treatment to exterminate the mold and bacteria from the roof. Our Soft Wash roof cleaning process will ensure that your roof not only looks great, but that all of these organisms have been completely killed, and that your roof has a much greater chance of reaching its full, expected life cycle — saving thousands of dollars in premature replacement.”

Since the process is applied through agricultural sprayers in many cases, Envirowash doesn’t even have to get on the roof, and can work from the ridge lines. Remember, “It’s not old, it’s mold.” Contact Envirowash for a free onsite estimate or demo, or for more information on exterior cleaning concerns.

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