Noticed spots on shingles with stones missing?

I noticed tonight while cleaning gutters that there were some spots like white moss about dime size on my roof that when I touched them flaked off with the stones whats the deal ??

Hopefully this doesnt mean roof failure, its only 12 years old …



Zinc strips (shingle shield) will help to prevent this from getting any worse.
It will not however get rid of the existing spots.
You can clean it off with Shingle shield roof and deck cleaner.
You should be able to get both products from your local roofing/siding supplier.

I am sure that they know you by now.

If they do not have the specific product I listed, I am sure that they have something equivalent.

White spots ,loose granuels, Sounds like hail damage

That’s NOT hail damage.

That is algae blooms feeding off of the organic compounds.

I would bet that all of these spots are in the shaded areas of the roof, right?

Once the algae is brushed off, the bare spots of asphalt will be revealed and look identical to substantial hail damage, minus the indentations on the shingles.


Yup, NO hail here it is in a shaded area. After cleaning/ zinc strips to sop any further how much damage or shortening of my roof life has occured ?

Any chance I will still see another 10yrs with NO leaks or will these spots now leak.


Worrywart :roll:

liked bushogs guess.


No its not hail damage we have not had any hail here in years. It is a white like moss spot.

Will these spots cause a leak ?? It just looks like when the moss flakes off it takes most of the stones with it.

Again what kind of damage has this caused

I had removed the granules that protect the asphalt mat from the UV ray of the sun. Eventually the UV’s will breakdown the asphalt and begin to expose the fiberglass and eventually the shingles will begin to leak. Don’t despair though it takes YEARS for that to happen.

Take a whole bunch of pictures of your roof and post them up, we will tell you what is up with it.

I just ran into that on my Parents Lake Home in Wisconsin.

It is algae blooms growing on the asphalt.

When you try to gently dust off the algae, the already loosened granules come right off with it.

There will also be multitudes of other spots that are already barren and void of any sign of the algae and any granules, because they have been washed away from the storms in the past after they have grown large enough and dislodged the granules significantly enough.

Actually, at that point, it would potentially be an insurable event, if the storms rain eroded away the protective granules surfacing.


Sold a job this afternoon and the home owner said they had a friend who owned a commercial roofing company drop off some copper strips. There is more than enough there to go on both sides of the 110ft of ridge, 4 inches tall. They said if they needed more to just call they would bend and drop off more, for free.The stack was too heavy to lift up one end.

Don’t think they will have to worry about algae or moss!!!

I’ve found that some algae or moss once removed looks a like hail. There is of course to breaking of the matting in any way but it leaves a nice round uniform area were the granuals came off.

By “years” you mean maybe 10 more years ?? Isn’t there a shingle under the top one so even if it did eat away at the top shingle there is still another surface of shingle under that ??

I took the pics but you cant really see it. I KNOW its algee as I can see the spot then you brush it off and it leaves no stones.

Do the new algee free shingles stop that ?? Also my neighbor has a black roof and his seems fine, also no streaking that can be seen like on my peweter colored roof :o

The AR, Algae Resistant shingles have a zinc/copper implanted inside of the exterior time release ceramic coating, which is a patent by 3-M corporation.

The guarantee on the AR portion of the warranty is for the first 10 years, if I am not mistaken.
The slow time release dissolving of the exterior coating allows the metallic compounds to create a chemical reaction every time fresh rain washes over the shingles and through electrolysis, the new growth of algae is inhibited.


If there is a moss/algae problem on the existing roof we still install shingle shield on the new one.
It is too early to tell how well the new AR shingles perform in this respect.

So…if you just have a handfull of spots like I do that this has happened to will the roof probably be ok for a while yet ??

I think I will go black the next time as it seems they dont show the streaks

It does not matter what color the roof is, there should never be streaks to be seen in the first place. If you do it means the roof was installed without proper venting and you are going to need a new one in the near future.

Black streaks on the north face of the roof are caused by “BLUE GREEN” algae that is in the air. That is the only algae that the AR shinlges will resist. Black streaks have nothing to do with improper instalation or ventilation. AR shingles also do not resist moss…trim trees 15’ away from roof edge.

I never heard that one before.

Well a house we did years ago had the algae on it youre talking about. We tore it off, vented it properly and now 12 years later shingles still look like new. Oh well, perhaps I am wrong but if you think black streaks have nothing to do with improper ventilation then I am pretty sure everyone in wisconsin has a lot of Algae problems. Even the houses that are only 8-10 years old in subdivisions with no trees anywhere in site. If algae is the problem then what is going on with the houses up here? I would like to know your opinion so I am not lying to the customer. When I went to courses to get certified by the air vent corp I was told something different. If we are all wrong, please do let me know.

I realize that may sound like I have an attitude but I dont. I am confused.