Alge Stains on Roof shingles

[beersngars]

Thought I would ask fellow TBNer's if anyone has first hand experience removing the alge stains from roof shingles. I have read many different recipes on how to get them clean. Some say TSP and clorine bleach in anywhere from a 50/50 mix to 25/75 (bleach and water) and a few spoons of TSP per gallon to a cup. Others say forget clorine bleach and use oxygen type bleach such as OxyClean and water. Of course there are premixed solutions with all kinds of claims, but most seem rather expensive. I have a backpack sprayer and will do the job myself.

 

[beenthere]

About any of the solutions will kill the algae. Some water with bleach will work, but if it is a layer that has some thickness to it, may take longer than you want to wait.
Might apply it and then hose it off clean, figuring the solution will break the connection to the shingles.

For long term prevention, a ridge cap of some galvanized metal or copper will keep the algae from forming in the first place.

 

[CharlieS]

on my vinyl siding about once a year, i use a 50/50 mix of bleach/water in a garden sprayer. let sit a few minutes and blast it with the garden hose w/ a pressure nozzle. should work ok on asphalt shingles.

 

[Soundguy]

lowes sells a jug of stuff with hand pump sprayer that is for asphalt shingles, vinyl siding and painted stucco and concrete for removing algea stains.

soundguy

 

[merrickvilleguy]

ive had success with liquid algaecide for pools sprayed on and left for a while and hosed off ... keeping trees a distance from the house helps with circulation and will help keep the roof dry and limit regrowth too

 

[rekees4300]

I recommend "Wet and Forget". Used it this summer and it works great. Just spray it on your roof and you're done. Requires no scrubbing or rinsing. You can get 1 gallon at amazon.com for $27 plus $10 shipping. 1 gallon makes 6 gallons of ready to use product, which will cover approximately 2000 square feet.

 

[wedge40]

Will galvanized leaching kill Alage? I know my aunt and uncle had streaks on their roof and they came out cleaned the roof and put a cap of galvanized metal on the roof.. No more streaks.

Wedge

 

[beenthere]

I recommend "Wet and Forget". Used it this summer and it works great. Just spray it on your roof and you're done. Requires no scrubbing or rinsing. You can get 1 gallon at amazon.com for $27 plus $10 shipping. 1 gallon makes 6 gallons of ready to use product, which will cover approximately 2000 square feet.

You can, but bleach in the Chlorox bottle is much, much cheaper.
The only reason to rinse is to get rid of the dead algae after the bleach kills it.

 

[Soundguy]

Will galvanized leaching kill Alage? I know my aunt and uncle had streaks on their roof and they came out cleaned the roof and put a cap of galvanized metal on the roof.. No more streaks.

Wedge

interesting that you mention that.

I have a concrete drive that gets the normal black algea on it in the pores of the concrete.. except about a 3' area around a gat that sets over the drive. it's it brite zinc plated... concrete is completely clean under it and in it's drip line and an area about 1.5' on either side of it.

does make ya think don't it.

I had heard copper killed some stuff.. and silver too...

soundguy

 

[beenthere]

For additional proof of the galvanized metal, look at about any barn roof that has a galvanized cupola on it, and see the clean streaks on the shingles below that cupola.

Some people, that put natural wood siding on their homes, will place a copper wire just under the lower edge of a row of shingles (or siding) that will keep the mildew off the siding for many years.

 

[radioman]

prevention is the best option. scrubbing asphalt roof is a bad idea. You don't want to remove any of the rocks embedded in the tar felt.

I'd spray bleach if the roof is white otherwise use a commercail product. I would add a exposed strip of copper or zinc just under the top row of shingles on roof and let the rain do its work.

 

[scott_vt]

Good Afternoon Greg,
I was just looking up at my roof on the rear side, north side of the house, and thinking what my best options were ! So glad you brought it up !

The house was built in 83 so we are closing in on 30 years, so Im not sure how much more I can get in longevity out of these shingles anyway...

What has saved the roof in my opinion to date, has been the shade it has recieved...

The shingles are still not curled or cracked after all those years, so I guess that says something about sheilding against direct sunlight !

Before reading your thread I was thinking along the lines of a 1/4 Clorox to 3/4 water solution and one of the old indian tanks we use over the FD for a long distance spray... I will be keeping my eyes open for other good suggestions like the galvanized strip the others suggested !

Geee after looking at that photo I just took closer, there isnt much in the way of algae anywere near that copper flashing on the chimney...

 

[beersngars]

Thanks for all the replys. After a bit more reading, I have decided to try a concoction of 1 gallon of 6% sodium hypochlorite (Clorox), 4 gallons of water and 2 cups of trisodium phosphate (TSP). I will spray in on and let it sit for about 15 minutes and then hose it off.

As far as the preventitive measures of copper and zinc, a lot of the success of depends on your roof design, pitch and the shade/sun factor from my reading. I will let you know how my plan works out. It may be a week or two before I can get to it.

 

[buckeyefarmer]

I recommend "Wet and Forget". Used it this summer and it works great. Just spray it on your roof and you're done. Requires no scrubbing or rinsing. You can get 1 gallon at amazon.com for $27 plus $10 shipping. 1 gallon makes 6 gallons of ready to use product, which will cover approximately 2000 square feet.

I got it at costco. haven't tried it yet.