For the past 30 years I have done the following:
Dilute plain laundry bleach with water, one part bleach and three parts water. Apply with a pump garden sprayer. Apply when the moss is reasonably dry and thirsty like several days after the last rain. Wet it all; any you miss will not be killed.
In a few days the moss will turn brown and can be swept/brushed away. I just leave the dead moss alone and eventually it will go away. Anyone concerned about the bleach on the roof understand that sunlight will neutralize the chlorine shortly.
By Caidok from Poulsbo, WA
Great idea. My only problem is getting up on the roof. Perhaps a handyman can help?
How long do you allow the bleach solution to soak into the roof moss? Do you rinse with water afterwards?
By Bruce T from Victoria, BC
I use dollar store (or any powder) laundry detergent. Seriously. If scattered on the moss, it turns it brown and kills the roots. You then simply brush it off with a brown.
As a former property manager, I used this method for my sidewalks. It's cheap and easy to do. I hope this helps. Here are some other things you can do.
Can I use Dawn dish soap and water to get rid of moss on an asphalt roof?
It will make so much slimy work it isn't worth it. I used dollar store laundry detergent, sprinkle it on and in four days it is brown and the roots are dead. Most of the time you can just brush it off with a broom. I hope that helps.
I am at the moment using a regular broom can I use a wire brush?
By Joan A from Courtenay, B.C.
You never want to use a wire brush on shingles of any kind especially asphalt shingles as it will begin to remove the little rocks that protect the shingle. Just a nylon scrub brush should do the trick.
I was wondering if anyone knew how to remove Moss from my asphalt roof tile. I remember hearing about a laundry detergent but I can't remember which one?
Laura From BC
I used Round Up. It killed the moss but now I have the problem of removing the dead moss. Maynbe it'll dry up and blow away if the sun ever shines. Good Luck Laura in BC (08/05/2004)
If they are Spanish tiles you do not want to walk on top of them, as it can damage them and are very costly to replace. Then that poses another problem, how to replace them correctly so you have no leaks. I would use the round up as suggested. Keep an eye on your gutters as the rain run off might carry the moss down your gutters and get stuck in the gutters.
I understand that a mixture of bleach and water works just fine. I just cannot find what the proportions are. The last I knew it was like 1/2 cup bleach to a gallon of water. (11/09/2004)
I have used Tide with bleach on an overhang, which seemed to work well enough where the rain doesn't continually fall upon it. I have tried it on the North side of the roof of about 500 sq. ft. using a whole box (7 lbs.) and was not satisfied with the results. Plain Tide white powder (no bleach) works well or zinc strips work the best. Bleach can have reactions with the roofing materials. (01/11/2005)
As an owner of a moss removal company, there are many remedies for this, some of which I agree and disagree with. My method is zinc sulfate but we first remove the moss first with a brush and then apply the zinc. My mission is to find a product that is safer for the environment. Even with minimal coverage of zinc in the long run it is not the best for our future. (03/20/2005)
I heard just the other day that the detergent to use is Ivory Snow. It only comes as flakes. I presume you would dissolve it in water, but I don't know. (09/26/2005)
By Michael, Vancouver B.C. Moss Capitol of the World
You want to use zinc sulphate to kill the moss first. Once it is dead, then you brush it off with a steel bristle brush by hand. After doing about 3 rows of shingles, use a blower to clear the area. This makes it safer so you don't lose traction on the loose moss. You can read more information about roof moss removal at http://www.bradlewis.com. If your roof is steep enough and you don't mind looking at the dead moss for a while, you can let it weather off. It will clog up your gutters possibly. It depends on how big the chunks of moss are though.
Laundry detergent will work.
You can use Tide Laundry detergent or bleach to kill the moss.
If you use Tide, however, it will pull the oils out of composition shingles and cause the granules to drop. This kills the moss but destroys your roof.
You can use bleach, but I recommend zinc sulphate over bleach any day because it also prevents future moss from growing for at least a year if applied according to directions.
Mix for bleach water is 3 qts (1 bottle) of 6% bleach (Sodium Hypochlorite) to 3.75 gallons of water. This yields 4.5 gallons of water, almost a full five gallon bucket.
Wet the roof from the bottom up. (So you don't get drip lines as the bleach water bleaches out mildew stains etc.
Got some ideas from this page, will give them a try. (09/09/2008)
Lots of ideas here. The National Toxics Coalition recommends washing the moss off (you have to anyway), and using a small amount of zinc sulfate, preferably in strips, to prevent more moss. If you are using Round-Up or bleach, what is that doing to you, your garden or landscaping, and water downstream of you? Copper or zinc sulfate strips are the only long term way of eliminating moss. See askthebuilder.com for advice on how to install these. You can do it yourself, or hire someone. It doesn't look that hard.
I am a single mom and was up on my roof cleaning moss off (with my shoe!) yesterday. It worked! I did not use any water. It was a dry day, and I did not slip because nothing was wet. I think I'll be getting some zinc sulfate or copper strips next, and shoving them up under the top row of shingles on my roof. Even these release minute particles of toxins, but better slow release of minute particles over years than all of us dumping gallons of Round Up or bleach off our roofs every year. Let's stay posted for even less toxic solutions in the future. (06/28/2009)
The whole north side of my roof is covered with green sea urchins. Oak tree over roof. I went on GAF's shingle web site,use NO bleach! It dries out the shingles. I bought liquid copper at Home Depot, read the warnings, too dangerous to use, Do not use on roof. I went back and bought Moss Off, was supposed to be harmless to the house and dogs, etc.
Wrong! Zinc sulfate. Used it anyway through Miracle Grow hose thing, sprayed on roof, got none on me, half hour. later my face, eyes and arms were burning for 4 hours. It hardened into cement in the spray thing and has not killed the moss. I am looking at PH now, I guess moss likes acidity, (oak trees) lime or ammonia might do it as a neutralizer to acid,and won't poison my dogs. Of course,I am not sure what lime will do to the roof, they say Calcite or Dolomite lime. Then I was thinking Dawn dish detergent. I will find something, eventually that won't kill us and the roof. It's too bad about bleach, I almost used it,. It would have worked. I will NEVER fool with that Moss Out again! Safe, no it isn't! I'm going to check out that Round UP also. (07/21/2009)
By Buster 23
To: guest post: 3 parts water and 1 part laundry bleach apply with a pump type garden sprayer.
It works, I have used it for over 30 years. (03/28/2010)