Advice for moss and algae on asphalt roof shingles

bobm3 · 2009-11-27T00:56:15+00:00

I had new roofing installed (GAF 50 year asphalt shingles) about 5years ago. I've noticed that over the past year its started todevelop growing moss and algae on certain sections which are locatedunder tall oak trees. The old roof, under the same trees for 30 yearshad NONE of this growth. I've also noticed that on one side of myhouse, the same end of the house with the roof moss, has algae growingrelatively significantly on my white alum siding. Again, only thepast year or so.This side is south facing and there are no side trees blockinghorizontal sun exposure.So, my questions are:What might be causing this condition starting only this past year?What damage is being caused by the moss on the shingles?What could I do to eliminate and prevent future growth?Any possible recourse with the shingle manufacturer?Thanks for any/all advice provided.B

Nov 27, 2009 28 Replies

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Red Green 16 years ago

snipped-for-privacy@mucks.net wrote in news: snipped-for-privacy@4ax.com:

Nice suff...Wonder if Rover will be rigid yet when Mr Fixit comes off the roof.

[from the link]

Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, .... ADBAC is highly toxic to fish (LC50 = 280 ?g ai/L), very highly toxic to aquatic invertebrates (LC50 = 5.9 ?g ai/L), moderately toxic to birds (LD50 = 136 mg/kg-bw), and slightly toxic to mammals (LD50 = 430 mg/kg- bw).[4] Benzalkonium chloride solutions of 10% or more are toxic to humans, causing irritation to the skin and mucosa, and death if taken internally.[5]

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Bob M 16 years ago

Wow! Thanks everyone for quite of bit of education. I am going to try the product mentioned first and next spring try the zinc plates for an ongoing effect.

Thanks again all - this was great!

Bob

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salty 16 years ago

If by "weedkiller" he meant Roundup, then it was quite eco-friendly. The stuff is approved for use on food crops.

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tnom 16 years ago

10% ? The concentration of Benzalkonium chloride in the use of this product is not even close to 10%

Internally? Do you take gasoline, bleach, or bullets internally? If so then I would also be concerned with Benzalkonium chloride.

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Jeff The Drunk, BITCH 16 years ago

You're right!

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Tony Sivori 16 years ago

I don't know where you got that idea, given that I've never posted my position on that topic.

So many companies greenwash their product that the "green" or "Environmentally friendly" tags have become meaningless advertising fodder.

That said, I am substantially more concerned about environmental issues than many of my peers and acquaintances.

There are things that were commonplace in the old days (say, 35 years ago) that I would not consider doing today. A few examples: dumping used motor oil into soil as fence line weed killer. Gasoline as parts wash, then dumped on the fence line as weed killer. Venting freon to the atmosphere, both to repeatedly refill leaking systems and for actual repair.

As far as necessary use of chemicals (and other goods), I want products that work. If there are choices that are truly better for the biosphere, and the purchase cost different is not too great, I will go with the "bio friendly" option.

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Tony Sivori 16 years ago

Thanks for that. One more question (that I should have asked the first time), what is the percentage listed on the label?

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Phisherman 16 years ago

I used the product "Shingle Shield" which are zinc strips installed near the roof peak, that was nearly 20 years ago. Today there are shingles made that release metal ions. For existing conditions you might try a moss/algae killer product (hardware store, HD, Lowes). Increase the sunlight and airflow to your roof (remove a tree or two?). Increase your roof's pH. Decrease moisture--Check drains/gutters. Your trees are probably giving you a lot more shade than 5 years ago.

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aemeijers 16 years ago

Careful, a reasonable opinion like that could get you kicked out of here.

-- aem sends....

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