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Gemstone
Premium
join:2000-12-20
Long Island

Lichen on roof removal?

I have green lichen growing on one area of my north facing roof. My roof is normal asphalt shingles and about 20 years old. What is the best way to safely remove the lichen without damaging the roof?
--
Go Mark Martin!



Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4

The obvious thing is you do not want to scrub it, as that would damage the shingles, especially given the age of your roof. I have not seen it done myself, but I have heard that using a good bleach and water mix is the best formula. Some people say to add a few drops of dish soap to act as a surfectant and let it grab onto the surface better. Spray it on the lichen, and repeat daily for a few days. Once the lichen dies it will dry up and mother nature will dispose of it without you having to use any manual removal.



CylonRed
Premium,MVM
join:2000-07-06
Bloom County
reply to Gemstone

Zinc strips on the roof is supposed to help prevent if not stop the chance for lichens to grow on the roof.

»www.ehow.com/how_5794685_remove-···les.html
--
Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain



Gemstone
Premium
join:2000-12-20
Long Island
reply to Lurch77

Yeah, I don't want to do anything abrasive to the roof shingles... I have no leaks or problems, but at 20 years old I need to be careful... Not ready financially to have the roof replaced yet... Do you have any idea of the mixture ratio of the bleach/water mix?... Doing a Google search brings up alot of commercial products... Some for mold, some for black streaks, some for lichen (I think)... I have no idea if any of them are good...
--
Go Mark Martin!



CylonRed
Premium,MVM
join:2000-07-06
Bloom County

Check out the link already provided.



Lurch77
Premium
join:2001-11-22
Oconto, WI
kudos:4

Just keep in mind that those directions appear to be for a wood shingled roof. You shouldn't scrub or scrape asphalt shingles. And obviously step seven is complete irrelevant in this case.



alkizmo

join:2007-06-25
Pierrefonds, QC
kudos:1
reply to Gemstone

said by Gemstone:

Yeah, I don't want to do anything abrasive to the roof shingles... I have no leaks or problems, but at 20 years old I need to be careful... Not ready financially to have the roof replaced yet... Do you have any idea of the mixture ratio of the bleach/water mix?... Doing a Google search brings up alot of commercial products... Some for mold, some for black streaks, some for lichen (I think)... I have no idea if any of them are good...

you better make sure you can get a heloc or small mortgage for the day that roof needs replacing. Better that than being in debt on high interest personal loans,


CylonRed
Premium,MVM
join:2000-07-06
Bloom County
reply to Lurch77

I hate when they never mention the shingles - did another search and got this - »www.ehow.com/how_10048473_remove···les.html

Steps are very similar though more gentle...
--
Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain



Gemstone
Premium
join:2000-12-20
Long Island
reply to alkizmo

I have no idea what a "heloc" is but not looking for financial advice... Just lichen removal advice...
--
Go Mark Martin!



IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7
reply to Gemstone

said by Gemstone:

I have green lichen growing on one area of my north facing roof...
...My roof is normal asphalt shingles and about 20 years old...
...Not ready financially to have the roof replaced yet...

if its not leaking and not falling apart, leave it alone until you get the funds necessary to have it replaced.
--
Suffolk County NY Police Feed - »www.scpdny.com
PS3 Gaming Feed - »www.livestream.com/elitedata


netboy34
Premium
join:2001-08-29
Kennesaw, GA
kudos:1

1 edit
reply to Gemstone

Home Equity Line of Credit

I've also heard this spray and forget works well... I haven't used their roof one, so I can't say it works... but if it works like their house wash/desk wash product, I'd say it would be worth a try...
»www.homedepot.com/p/t/202807381?···Jbl_D-M8



Shadow01
Premium
join:2003-10-24
Wasteland
reply to Gemstone

With the low cost of bleach, I use a 50/50 mix in a chemical sprayer and use as needed during the year.



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
reply to CylonRed

They supposed to, but they don't work too well. I have a zinc strip on my roof, and it stops them for a couple of feet, but green stuff grows just fine a bit further away.

I'd try a non-staining moss kill -- the OP would need to apply it at least a couple of times per year, though. I actually have a bottle and should've done it weeks ago, but I can do it some time when the forecast is dry for a little while, and snap some before and after pictures.
--
Wacky Races 2012!



CylonRed
Premium,MVM
join:2000-07-06
Bloom County

It would seem to me then, that the strips need to be installed across the breadth of where the growing conditions are met. All of the install instructions I have seen usually calls for strips top down - not just one strip at the top of the growth.
--
Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain


Pher9999

join:2011-07-06
Carmel, NY
reply to Gemstone

a Few years ago they did this on Ask This old house. cover the plants around the base and it was a bleah water mix.


robbin
Premium,MVM
join:2000-09-21
Leander, TX
kudos:1
reply to IllIlIlllIll

said by IllIlIlllIll:

said by Gemstone:

I have green lichen growing on one area of my north facing roof...
...My roof is normal asphalt shingles and about 20 years old...
...Not ready financially to have the roof replaced yet...

if its not leaking and not falling apart, leave it alone until you get the funds necessary to have it replaced.

That would be my suggestion. Even just killing the lichen and having it slowly wash away could create as much damage as what is happening now. Lichen is very slow growing and should not significantly shorten the life of a 20 year old asphalt shingle roof. If the green growth is moss and not lichen then my answer may change.


norton

join:2005-08-03
Howard City, MI
reply to CylonRed

+++ on zinc stips AND as i also have a brick house in deep woods. I use 30% vinegar solution in sprayer to wet surface where anything green starts appearing. (I don't even always hose off vinegar let it keep working)



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
reply to CylonRed

Click for full size
That roof is 6 ft deep, and looks to me the zinc strip is effective for no more than 4 ft.

It's a bit over 3 years old (this was its 3rd winter) and I thought the zinc strip (installed right after the shingles) will be enough to keep the moss away.

As it can be seen, the moss have proven me dead wrong.

Although I have a feeling that in a couple of weeks that moss will be very dead.
--
Wacky Races 2012!


CylonRed
Premium,MVM
join:2000-07-06
Bloom County

In the links I have seen - depending on the conditions - more than one horizontal zinc strip can be needed.
--
Brian

"It drops into your stomach like a Abrams's tank.... driven by Rosanne Barr..." A. Bourdain



Pacrat
Old and Cranky
Premium,MVM
join:2001-03-10
Cortland, OH
kudos:2
Reviews:
·Time Warner Cable

I've seen zinc strips installed lower on the roof... several feet from the peak, to allow more rain to flow over the strip and pick up more ions in the water. The peak-most arrangement allows only that water that falls on the strip to become effective, while a lower position exposes the zinc to more water flow.
--
Keep your eye on the ball, your shoulder to the wheel, your nose to the grindstone, and your ear to the ground. Now, try to work in that position!!!



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1

I think I should have enough zinc to add at least one more strip across.



VioletVenom
Lets go Gators
Premium
join:2002-01-02
Gainesville, FL

Yikes aurgathor! Going by your picture the problem is using 3 tab shingles on a pitch shallower than a 3/12. I would be surprised if you have any roof deck under that moss. Moss is thriving from moisture in that area of the roof. I would guess that area is one big sponge. Any pitch less than 3/12 needs another product, like a rolled roof. Although roofing technology has jumped ahead and there are much better products for shallow pitched roofs.


boaterbob
Premium
join:2005-08-01
Moncks Corner, SC

I had this problem when I lived in High Springs (Gainesville), Fla. and I used a pump-up garden sprayer to spray a bleach/water solution. The lichen was killed but then it turned reddish/brown in color - it does not disappear for quite awhile - long time - i.e., not quickly!! Your choice - green and alive, or reddish/brown and dead.



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
reply to VioletVenom

said by VioletVenom:

Going by your picture the problem is using 3 tab shingles on a pitch shallower than a 3/12. I would be surprised if you have any roof deck under that moss.

The wood underneath the tar paper is coated with poly.

There's a long story to the slope -- suffice to say that making it significantly steeper would've made the space underneath much less usable.

Any pitch less than 3/12 needs another product, like a rolled roof.

Next time.
--
Wacky Races 2012!


Coma
Thanks Steve
Premium
join:2001-12-30
NirvanaLand

said by aurgathor:

said by VioletVenom:

Any pitch less than 3/12 needs another product, like a rolled roof.

Next time.


Last year, I replaced a 38'x10' awning over my back porch with a standing seam metal roof. It should last my lifetime with years to spare.

--
March is National Noodle Month