How do you clean your roof shingles that's stained from mold & sap

Try a product called wet and forget. It's great at taking mold off and keeps it off. You can get it at ace hardware

Hey, great, I am trying to find a product for my siding and also came across wet and forget. I am going to purchase some and see if it works but I was hesitating until I saw this answer. Thank you.

The black mold-like stains and streaks that appear on roofs, particularly light-colored asphalt shingles, is actually a blue-green algae (Gloeocapsa magma). Commonly found in climates with warm, humid summers, it does no damage to the roofing, but it certainly does looks bad.

The less expensive solution is to spray wash the roof with a 50 percent mix of water and bleach to get rid of the algae. (No pressure washers, please. They're likely to damage the shingles.) Just be sure to wet your foundation plantings first, and rinse everything in clean water when you're done. Plants don't like bleach, and wetting them with plain water first protects them. You can also cover them with tarps or plastic sheeting, which will protect the soil around your plants as well. Make sure that you create a wide radius around your home to be safe.

Allow the solution to soak into the shingles for at least 15 minutes. If they are severely molded, you may want to give it a little longer. Next, rinse the shingles thoroughly with a garden hose at low pressure. Start from the top shingle and rinse downward to prevent water seepage.

To keep the algae from coming back, insert 6-inch-wide strips of zinc or copper under the row of shingling closest to the roof peak, leaving an inch or two of the lower edge exposed to the weather. That way whenever it rains, some of the metal molecules will wash down the roof and kill any algae trying to regain a foothold on your shingles.

You can probably see this same principle working on roofs in your neighborhood. Look for chimneys with copper flashing; the areas directly below the flashing will be free of any algae stains.

The strips also work on roofs suffering from moss buildup. Just scrub it off first with a brush, then bleach as above.

Here is a link to 'Wet and Forget. http://www.askwetandforget.com/portfolio/faq-will-wet-forget-kill-my-plants/

Note that you can also kill mold and algae with white vinegar or hydrogen peroxide. Use a sprayer to apply. Bleach works too but does not penetrate porous surfaces like wood so it will come back. Vinegar should should be rinsed off be cause because the acid stays behind when it evaporates. Cover your plants around the foundation and then spray it off. Mineral spirits can be used to remove sap but only by putting it on a cloth and rubbing the sap off; never pour it on the roof. Note also, that once the mold and algae is killed it may be washed off by and eliminated by the elements the same as Wet and Forget.

Here is a link to 'Wet and Forget. http://www.askwetandforget.com/portfolio/faq-will-wet-forget-kill-my-plants/

Note that you can also kill mold and algae with white vinegar or hydrogen peroxide. Use a sprayer to apply. Bleach works too but does not penetrate porous surfaces like wood so it will come back. Vinegar should should be rinsed off because the acid stays behind when it evaporates. Cover your plants around the foundation and then spray it off. Mineral spirits can be used to remove sap but only by putting it on a cloth and rubbing the sap off; never pour it on the roof. Note also, that once the mold and algae is killed it may be washed off and eliminated by the elements the same as it would with Wet and Forget.