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Tips to Prevent Algae and Moss Growth On Your Roof

Have you ever seen roofs with dark streaks on them? Does your home have this problem?


There's a reason for this phenomenon on an aging roof, and there are ways to manage it and minimize it!


Sure you may just think it's unsightly and a "cosmetic issue".... or it's "normal" for roof staining.


But is it really? Can this eventually affect the performance of your roof over time?


Depending on the type of roof, there's a real possibility of it which you will see examples of as your read on.


A roof is one of the biggest investments that a homeowner makes within the course of home ownership.


Often times poor roof planning and maintenance can cause:

  • Premature roof failure
  • Energy inefficiency which increases power bills
  • Reduced curb appeal

We believe it should be every homeowners goal to minimize the number of times your roof is replaced over the course of ownership... and this comes in part with proper planning and maintenance!


Do you buy a car out of the dealership, drive off the lot, and never change the oil, rotate your tires or change your air filter again?


NO! People would think you're crazy! So why do we do that with our roofs?


We are here to make sure you know how to properly select and care for your new roof.


Here are four helpful tips, to help you prevent algae and moss growth on your roof.




Tip #1 - Ensure Your Roof is Adequately Ventilated!


Whether you have a new or old roof, you can maximize its performance by installing proper ventilation. There are many types and forms of ventilation, both active and passive.


In Hawaii, the most popular type of ventilation are ridge vents, and solar fans!


Ridge vents are a passive form of ventilation, and many manufacturers include them within their roofing system warranties. They are a safe and reliable option for venting out your roof.


Paul Trepete (C3)


Solar Fans are an active form of ventilation. A solar-powered fan is used to suck air out of the attic space of your home. During the hotter, sunnier times of the day your fan works the hardest for you!


David Von Almen (D8)


Proper ventilation helps reduces hot humid air in your roof deck, and helps create an environment where mold and algae do not flourish as easily.




Tip #2 - Cut Back Overhanging Trees!


Trees that overhang your roof pose multiple risks to your roof. Aside from the tree branches rubbing up against your roof deck, and accelerating degradation... Trees also shade your roof and drop leave on them.




This holds moisture on your roof deck, and becomes a breeding ground for microorganisms on your roof! It is common for the perimeters of your home and the valleys to build up with fallen leaves and branches. These areas MUST stay clear to allow water to properly flow.




It is recommended to have an arborist or landscaper cut back the trees that overhang your home, to reduce dead leaves, heavy branches and unnecessary moisture from spending time on your roof and rotting out the roofing material and roof deck itself!


NOTE: We do not recommend you trimming trees yourself without proper safety equipment or training. Some things are best to leave to the professionals!




Tip #3 - Install a Roof with a good Algae Resistant Warranty!


Rachel Moorehead (C1)


Most manufacturers that supply shingles to Hawaii come with algae warranties that come with a 10-25+ year algae warranty!


The granules that cover asphalt shingles compose of special formulations which often contain elements such as copper or zinc to help kill bio-mass that may accumulate on your roof over time.


We recommend GAF Material Corp. for their StainGuard Plus Warranty!


Edward Quon (D4 - E)


Among the various shingles available in Hawaii, GAF offers one of the best options when it comes to Algae Resistance (AR) amongst other things.


GAF shingles come with a 25 year Algae Resistance (AR) warranty. This provides an unbeatable value as most other competitors currently offer a 10-15 year warranty.  Selecting a roof that will "stay clean" is important when planning your next roofing project.


The best part? The costs for these types of shingles are in line with most of the other competitors. It is not the cheapest shingle on the market, but when it comes to your biggest investment... most times, you don't want to take short cuts.




Tip #4 - Consider Periodically Soft Washing Your Roof!


Before Soft Washing

Before Soft Washing


For an existing shingle roof, or other roof types such as mod-bit, shake, tile or metal roofing... there are no algae warranties available.


This means that proper maintenance is required to help your roof stay fresh.


A softwash is a non-invasive and eco-friendly way to clean your home. It comes at a relatively low cost, and is a quick and easy way to improve curb appeal and performance while maintaining your investment.


After softwashing

After Soft Washing


It avoids "pressure washing" your roof, which has the potential to cause damages, and instead using a low-pressure chemical cleaning to remove the debris and organisms that are growing on your roof.


Here at Kapili, we believe that we should not only help you identify your roofing problems, help you select the right roof for you, and deliver a great roofing experience... but we should also help you get the most out of your roof after it has been installed!


As part of our menu of services to local Oahu homeowners, we also offer exterior cleaning and softwashing services.




If you found any of these tips helpful, and you think you need any help with implementing some of these tips for your home. Please reach out to us anytime!


You can click below to book your free consultation, and our Customer Success team can help guide you through the process of having your home inspected, and help you understand what type of options you might have.CONTACT US