Frequently Asked Questions

The short answer is that it is algae. It grows on the north side and shaded areas of your roof. 

The long answer: Gloeocapsa Magma is the primary species of algae causing your roof to turn black. Milled or compounded limestone is used as a filler in roofshingles to add weight and flexibility for the shingle. Shingle manufacturers started using limestone, which is calcium carbonate, in the late 70’s when the first energy crises hit and petroleum became expensive and was in short supply. Limestone is apparently a superior filler product and most shingle manufacturers are reluctant to go back to the old methods or to try new products. The problem, is that algae loves limestone because of its alkalinity and solubility, it provides a stable environment and a food source for the algae to flourish. It thrives in warm, humid environments and normally appears on the north facing slope orshaded areas of your roof where the lack ofsun and abundant moisture (like morning dew) supports its growth. These Algae spores are carried by the wind and land on your roof. You may first notice it as little black stains on your roof that just seem to explode over the course of a year. It’s growth is exponential, the more it spreads the more moisture it can hold to aid it’s growth. As it grows, it will spread to adjacent homes which is why you will see it on so many roofs in the same area.

The shingle manufacturers say that while the algae is unsightly, it does not damage or harm the shingles. After many years in the roof cleaning business, I can say that it does seem to do some damage. Older roofs with a lot of algae seem to lose more granules. As the algae feeds and spreads, it loosens this protective layer ofsurface granules which play a very important part in solar reflectivity. The loss of these granules, combined with the black growth spreading across your roof will cause the roof to absorb heat from the sun up on a sunny day. Your attic will be much hotter than necessary and this usually translates to the upstairs of your home being a little warmer, as the heat from the attic radiates into that upper floor. While this might be fine in the winter, it can be a source of higher electric bills in the spring and summer months as your air conditionerstruggles to keep up.

The average roof cleaning will usually last three or more years depending on the amount ofshade around your home. If you are under a lot of trees and the roofstays shady for a good portion of the day, then the algae will certainly return a little faster. Homes that do not have many trees around them tend to stay cleaner much longer. Just remember, Heat and humidity play a big role in helping the algae thrive. We recommend signing up for 6 month check-ups and yearly treatments to help fight the algae.

The answer is yes. We have developed a few methods to effectively clean moss off of roofs. If you are dealing with a letter from your insurance company that is requiring you to clean the moss and algae of off your roof, please tell us about it when you call or email. We have helped many homeowners deal with that problem.

We use air powered pumps to lightly dispense the cleaning detergents on the roof. No pressure washers are used in our process. The detergents do all the work to clean the roof and we then rinse with garden hoses. This follows the method the shingle manufacturers themselves recommend, meaning no pressure.

There is no “recognized” certification process in our industry. Any claims to certification that you may see in the roof cleaning industry are usually nothing more than a piece of paper and a nice logo purchased online. There are several websites that have recently appeared, where, for a fee, anyone can subscribe and get some online roof cleaning training, a tee shirt and a certificate implying they are now certified to go clean roofs. So the answer would be no, we are not certified. We have cleaned many roofs in the local area and rely on that experience to provide a high level ofservice to our clients.

Bleach does not damage shingles. These days, most professional roof cleaning companies use bleach in their roof cleaning mix. The Asphalt Roofing Manufacturers Association (this would be the trade association that represents companies that make shingles) have said the proper method of cleaning a roof involving the use of bleach, soap and low pressure. The non pressure, or low pressure cleaning process is the only method approved and endorsed by shingle manufacturing companies.

Will your detergents kill my plants and shrubs?

I have seen instances where they have worked after a couple of applications and a couple of months waiting. The best way to answer this question would be to tell you to pick one of the products, then go to amazon.com orsimilar site and read the customer reviews

Based on our experience with them I would say they work, but only for a limited time. The effect of the strips seems to degrade over a period of years. There is also a distance factor. The width of the zinc strips determines how much area of the roof it can cover. We offer the service of installing either zinc or copperstrips for preventive measures in keeping your roof clean. As well as 6 month checkups and annual roof treatments

I have seen these companies and I am not sure how effective they are. They must first clean the roof and then apply the sealant. If it is something you are thinking about, we recommend doing lots of research because it seems like the process creates more problems than it solves especially with any warranties you may have.

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