How to remove moss from shingled roof?

  11 answers
  • Gk Gk on Jun 29, 2020

    Here's a few suggestions for you Ruthie! Please DO NOT use a power washer as it will take off important parts of your shingles!

  • Annie Annie on Jun 29, 2020

    You pretty much have to go up on the roof and carefully remove by hand without damaging the shingles. You can put Zink pellets up there or put a Zink flashing at ridge . This will help prevent moss for growing

  • William William on Jun 29, 2020

    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.

  • Lifestyles Homes Lifestyles Homes on Jun 29, 2020

    Bleach water and it will require a couple of treatments per growing season.

  • You can scrape it or clean it as suggested above. You might want to hire a professional. It's pretty dangerous to get up on the roof and start working and a professional will have the proper safety equipment.

  • Oliva Oliva on Jun 30, 2020

    Using a garden sprayer, apply Wet n' Forget to the roof. Over time, sun and rain will dislodge the moss. As William recommended, installation of a section of copper or zinc at the roof peak will alleviate this problem.

  • Johnavallance82 Johnavallance82 on Jul 01, 2020

    Hello Ruthie,

    Use a Power washer, but be careful not to use too much power for fear of removing more than just moss or Spray on Wet a Leave or Spray and Leave. and let that do the job for you over a few days/weeks.

  • Connie S Connie S on Feb 25, 2021

    Do not use a power washer, it damages the shingles. Bleach damages shingles over time.

    Living in the PNW, this us a constant problem for us. I will include a picture of how ineffective zinc strips are, on a small roof. You have to remove the moss, no product will do that for you. You can use a stiff brush and sweep of large chunks, a putty knife is my friend for gently scraping between and under the shingle edges. If you have visible moss, it's under these edges too Of all products, I have used, regular baking soda, (sodium bicarbonate) sprinkled on several times a year, has been the only thing to keep it away long term. The picture is of a small north facing roof, no over hanging trees. Zinc strip only kept a bit of that top, coming down from the peak, moss free. Expensive, for such little protection.