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waxman18324 · Premium Member Roof Cleaning Institute Of America

One Stubborn Roof Stain

A to Z · Deleted

I can't see to much with the picture. Could it be granule loss due to the amount of water that travels there?

larrykilby · May 13, 2012

Hank,

Has mother nature rinsed the roof yet? I have seen some stubborn stains that needed to be rinsed several times before it was gone.

Larry

gutterdog · May 13, 2012

for some reason I cant see it???

waxman18324 · Premium Member Roof Cleaning Institute Of America

Here are some before photos as well.

Hank

waxman18324 · Premium Member Roof Cleaning Institute Of America

larrykilby wrote:
Hank,
Has mother nature rinsed the roof yet? I have seen some stubborn stains that needed to be rinsed several times before it was gone.
Larry

Larry,

Yes, that roof has been rinsed by several rain storms since I did it. At one point is was close to 2 1/2 to 3 foot wide towards the bottom.

Zach,

I checked and the shingle doesn't indicate any great granule loss.

Hank

Roof Cleaning New Jersey · May 13, 2012

If it doesn't clean up, it's not GM

SEE OUR WORK HERE!!! · Guest

I ran across this a few times on algae resistant shingles, both at downspouts and along the sides of skylight flashing. My theory is these fairly new algae resistant shingles (within the last 15 years) contain copper additives to help prevent algae growth. The rain water flowing through the downspouts pick up trace amounts of aluminum from the downspout material, this rain water containing the aluminum reacts with the copper in the shingle and creates this staining. Copper and aluminum are on different ends of the galvanic scale and should never be in contact with one another. If contact is made, corrosion and staining will most likely occur. I see this all the time where roofers install a copper counter flashing over aluminum step flashing. It gets to a point where the aluminum be less noble, has been deteriorated by the copper which is the more noble metal.

Makes sense to me, remember it's just a theory!!!

waxman18324 · Premium Member Roof Cleaning Institute Of America

Ed and Barry,

I'm heading over there tomorrow and I'm going to give it one more shot. Wish me luck.

Hank

May 14, 2012

I am a little lost but I will take a shot. This stain is coming from the top roof correct? Since you are in the North could you have a " Soot Stain " from the chimney? Possible running down the roof...then into the gutter down the spout? Just a shot

Mr Maintenance · May 14, 2012

I had one of these stains and it hung there for weeks. It was a roof I cleaned not far from my home. I went buy it every 3-4 days and it was still there. The latest rain that came through NH was the trick. I went buy it Saturday and it was all gone. I think the leftover mix in the gutter kept cleaning it. Hank Keep us posted

waxman18324 · Premium Member Roof Cleaning Institute Of America

Charlie and Brian,

Thanks for the support.

Charlie, the chimney is on another roof of the house.

Brian, it's been raining on and off since I did this house. I was going to go over there today but they are calling for rain. The same for tomorrow. Wednesday or Thursday will be better weather.

Hank

Apex Roof Cleaning · Guest

Landis Roof Cleaning Eastern Pa 610-689-4475 wrote:
I ran across this a few times on algae resistant shingles, both at downspouts and along the sides of skylight flashing. My theory is these fairly new algae resistant shingles (within the last 15 years) contain copper additives to help prevent algae growth. The rain water flowing through the downspouts pick up trace amounts of aluminum from the downspout material, this rain water containing the aluminum reacts with the copper in the shingle and creates this staining. Copper and aluminum are on different ends of the galvanic scale and should never be in contact with one another. If contact is made, corrosion and staining will most likely occur. I see this all the time where roofers install a copper counter flashing over aluminum step flashing. It gets to a point where the aluminum be less noble, has been deteriorated by the copper which is the more noble metal.

Makes sense to me, remember it's just a theory!!!

Barry I think your exactly right, I have seen some skylights leave black streaks on a roof. I don't know which type of skylight, I think Charlie roof cleaning had 2 nice pictures of skylight jobs that left big black streaks.

Like Ed said if it doesn't clean its not algae.

You could always try calling 1-855-WASHME2 I am sure those guys would come out and help you out.

Try a 70% SH see what happens, if not I would see whats bobs gutter grenade does, isn't that suppose to help with corrosion?

waxman18324 · Premium Member Roof Cleaning Institute Of America

Dan,

Everytime I call that number I get message the technicians are in Philadelphia or are sleeping. Only teasing.

I tried pure sh on it, with no surfactant, but to no avail. When the weather breaks at the end of the week I'll go over there and try again. These shingles are over 18 years old so I doubt they are algae resistant.

Not sure about using Bob's stuff on it.

Hank

Apex Roof Cleaning · Guest

We got a job in this morning, but weather is suppose to be nice again by wednesday. Try bobs stuff I am really curious, its suppose to help with reversing corrosion. I don't think the algae resistant shingle is on this roof, but something to do with dissimilar metals.

Doug R · Guest

Use a small pump up sprayer or squirt bottle and very close to straight SH. Spray a very small spot and see if it cleans.

waxman18324 · Premium Member Roof Cleaning Institute Of America

Doug R wrote:
Use a small pump up sprayer or squirt bottle and very close to straight SH. Spray a very small spot and see if it cleans.

Doug,

Thanks but I've been there and done that as I noted in two of my posts. The customer was warned beforehand (gut instinct/woman's intuition/vibes) that this stain might not come out. They were ok with it but it's driving me crazy.

Hank

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