I live in the pacific northwest and all rain water goes directly to the lake near our house. So I don't want to use some harsh chemicals to remove moss from the roof. Are there any environmentally safe ways to remove moss and keep the roof dry and prevent moss from growing?

EDIT: The roofing material is asphalt shingles.

  • Aren't there certain materials of roof which naturally repel moss? Nov 12, 2017 at 23:55
  • @Harper yes Zinc - but it is harmful to the aquatic animals in his lake. the op will need to perform an upkeep regimen on the roof in order to be environmentally friendly to that lake.
    – Ken
    Nov 13, 2017 at 4:46
  • Why do you want to protect the environment in the lake, but not the environment on your roof? That moss is completely natural. It cleans the air and provides insulation for the house. The moss on your roof is part of a larger ecosystem that pre-dates your house. What right do you have to poison it? Nov 14, 2017 at 3:35
  • @BillyC. - Perfectly valid question. "What right do you have to poison it?" ==> I didn't say I want to poison it. I just want to remove it in a safe way so that the water doesn't get polluted. If the moss is not going to damage my roof then I have no problem with it growing on top of it and give a nice green color. I'd love that. On the other hand if its going to grow and cause damage to the roof, then I don't want to spend thousands of dollar to replace it.
    – yasouser
    Nov 14, 2017 at 22:44
  • Yeah, I thought about that. Poison is the wrong word. "Kill" or "displace" is what I should have said. The moss will be just fine on your roof. Removing it will only hurt it. Preventing it from growing there will disenfranchise the moss of its right to life. Nov 14, 2017 at 23:51

3 Answers 3


We use a bare galvanized wire fastened to the ridge of the roof.

If you’ve ever noticed a “clean” area under (downside of slope) chimney flashing or metal roof vents, you’ll understand the use of galvanized metal to keep the roof “clean”. (I’m sure some chemist could explain why the galvanized coating keeps the asphalt shingles “moss-free”. )

  • 1
    Fascinating. I've noticed this exact phenomenon on my roof. And I think it's stronger now that we had the chimney rebuilt and there is plenty of fresh flashing. Here's a link to a guy who uses zinc strips: structuretech1.com/zinc-strips-prevent-moss-growth-on-roofs
    – Stanwood
    Nov 13, 2017 at 2:51
  • He said Environmentally safe - he has a lake. Galvanized - think Zinc. Zinc Strips - think Zinc.. Zinc is bad for the aquatic animals.. The op is looking for environmentally safe.
    – Ken
    Nov 13, 2017 at 4:43
  • @Ken I don’t know if a galvanized wire on your roof is worse than a major baking soda and vinegar wash. The galvanized wash is slow and done slowly over time...and the runoff would need to make it to the lake. Unless the roof’s runoff is piped directly to the lake, it would probably dissipate into the soil...especially because it’s such a minor amount. I wonder if there has been any studies comparing galvanized tainted water verses baking soda and vinegar wash every year or every other year.
    – Lee Sam
    Nov 13, 2017 at 6:57
  • I agree and have usedboth zinc wire and strips about 1/2 way down. The zinc will last as long as the roof. As far as safe what are the annodes on boat motors? Zinc , what is the compound on galvanized pipe and metal water troughs? Zinc. It is safe.
    – Ed Beal
    Nov 13, 2017 at 15:38
  • @EdBeal and for others ..Notice what it says should be avoided .. so not safe for a lake.. bryophytes.science.oregonstate.edu/page24.htm Baking Soda converts the water to more alkaline killing the moss, Vinegar to more acidic killing the moss. I have not found any studies showing where the Baking Soda (sodium-bicarbonate) is harmful to aquatic life. As a matter of fact they use it when transporting fish in tanks.
    – Ken
    Nov 14, 2017 at 3:06

Baking Soda or Vinegar will work and it is better for the environment and animals than some harsher chemicals.

What this does is change the Ph level of the Moss to a point where it dies off - and it will take time for the moss roots to die off using baking soda - it will die completely roots and all with in 3 months - you should notice it starting to die very soon after application but the root system will take more time - 3 months.. (buy enough to cover your moss areas) - if the entire roof is covered you are in real trouble - the roof is too far gone and you can count on replacing it.

You can mix the baking soda with some water or use it directly on the moss.

Vinegar is more acidic it can harm different materials - so be careful if you use this route.

A nice link I found to expound on this further can be found [here^].1

You are probably aware of people using zinc strips to protect against moss growth - however this is not a good environmentally safe product. While it is very effective at prevention it can be harmful to aquatic animals.

And just to state this again

Don't pressure wash your roof.

EDIT 11/13/2017 To aid those who are banging this answer. I am not sure if they have done their research or just relied on common practices. Common practice does not make it safe. Simple searches on line for environmentally (eco) friendly treatments for roof moss, and also similar searches for harmful effects of zinc strips will prove out my answer. So in order to save some trouble I will provide some links.

As for Zinc and its effects when NEAR a lake where you can have runoff going into a lake or pond - please take note that it should be avoided - which is the OPS concern .. see this link :


More info on Zinc and aquatic animals and vegetation


High zinc levels can interrupt the metabolic activity in soils, as zinc negatively harms microorganisms and earthworms, slowing down breakdown of organic matter that provides basic nutrition to plant roots. Some plants are naturally more tolerant of high zinc levels in soils, such as grasses, while broad-leaf weeds may be more sensitive. Vegetable crops tend to be much more sensitive to zinc levels, according to the University of Michigan.

Baking Soda converts the water to more alkaline killing the moss, Vinegar to more acidic killing the moss. I have not found any studies showing where the Baking Soda (sodium-bicarbonate) is harmful to aquatic life. As a matter of fact they use it when transporting fish in tanks to maintain ph balance and also other helpful effects.

If you are really concerned about the Lake environment - don't use zinc strips or galvanized wire.

  • So you are saying my large metal tank with goldfish is bad for them? But you are willing to increase or decrease the PH to the point of killing a living plant in a short amount of time and don't think that is bad? Zinc strips work great here in the Pacific north west and if installed with the roof are very effective.
    – Ed Beal
    Nov 13, 2017 at 15:44
  • @EdBeal I sure am telling you that it is bad for the aquatic life but here perhaps you will trust somethign from the pacific northwest. bryophytes.science.oregonstate.edu/page24.htm
    – Ken
    Nov 14, 2017 at 2:53
  • @Ken So in the report you reference by the U.S. Forest Service, you’ll notice in the 6th and 7th paragraph it seems to indicate that too much zinc or too little (zinc deprived) is bad and can cause problems, (I.e.: health, reproduction, etc.). So, as my dad always said, “Too much of anything is bad for you...” I guess that goes for deprivation of zinc too. Like everything, it’s about balance.
    – Lee Sam
    Nov 14, 2017 at 5:09

I would recommend a pressure washer. If the roof is steep use an articulated man lift.

  • 3
    His roof shingles are made of what ? If Asphalt - a pressure washer will work like a hail storm and beat off the granules.
    – Ken
    Nov 12, 2017 at 22:53
  • 1
    Please don’t pressure wash your roof. Nov 13, 2017 at 3:38

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