In the Pacific Northwest, you can’t walk down a street without seeing a roof with fir needles, moss, or other debris on it.  We get asked by our customers what is the difference between algae and moss?  How can we treat it?  Basically algae are seen as black streaks on a roof, where moss is seen as clumps of green that look, well, like moss. Lichen (like the stuff that grows on our trees) is often seen with moss.

The reason moss is growing on your roof is simple. Moss spores are always in the air, but they will only take hold and grow in a hospitable environment. Moss loves a shady climate, acidic environment (moss grows optimally at a pH level of 5.0 to 6.0), and a moist/humid environment. It is no surprise then that Western Washington roofs are a haven for moss.

There are three effective ways to prevent moss growth.  Take away the shade, take away the moisture, or turn its environment extremely acidic or alkaline. Because it is virtually impossible to do the first two in the Pacific Northwest, we are left with option three.

The first step is to remove any existing moss using a leaf blower or hand brush.  If you have a composite or asphalt shingle roof, it is very important not to pressure wash it. Pressure washing can remove the shingle granules which help protect the shingles and ensure a longer life span.  Once you have the majority of the moss and other debris removed, it is time to apply something to kill the remaining moss.

There are a lot of chemical moss removers out there, but Baking Soda or Vinegar work just as good.  Using baking soda or vinegar can also be cheaper and is better for the environment and animals.  Since moss grows in a pH environment around 5.0-6.0, changing the environment to an alkaline level it will effectively kill the moss. This makes baking soda a great product to use.  By mixing it with water or by applying it directly, it can kill moss in yards, off of roofs or other unwanted areas.  Another household item you can use is white vinegar (making environment too acidic for the moss to flourish).   Using vinegar with a mixture of water and applying it directly to the moss can kill it. Be careful though, some acid products erode certain types of surfaces. By diluting the mixture you may prevent unwanted corrosion.

When using these items, keep in mind you are killing the moss, but the moss might not fall of your roof immediately. Depending on how long it has been there, it can take 2-3 months to come off.  Moss has a thick root system that sets itself directly into the granules of the shingles.  When the roof is treated, these growths die, but it takes a while for the root system to disintegrate and let go of the roof. For large areas of moss, a several treatments may be needed.

Although you may be tempted to clean your own roof, you are better off leaving it to the professionals.   Roof Cleaning is not as easy as you think and not always a job for amateurs.  In fact, it can be dangerous.  According to the National Safety Council, more than 8.5 million people were treated in an emergency department for fall-related injuries in 2009.

Although Town & Country Roofing no longer offers roof cleaning services, you can still contact your local roofing company and ask them to use eco-friendly products.  If they don’t use them, ask them if they will clean your roof with the product you provide, like baking soda. Costco carries a large bag of baking soda for a reasonable price.

A clean roof is indeed a welcome sight to behold, but it can be best achieved when you let the experts do the work.

For more information about Town & Country Roofing please call 360-704-7663