Best and quickest way to clean algae/mold off of 1st and 2nd story siding?


Hi everyone. I’m currently trying to find the quickest and best way to clean algae, mold and mildew off of siding that reaches the 1st, 2nd and 3rd story. I’ve seen videos of company’s spraying on chemical, letting it sit for a couple minutes and then spraying it off no problem. They don’t need ladders, 2nd story wands or anything else. I basically am trying to get it where one employee can do a 3,000 square foot siding home by himself in the quickest way possible. Right now we are using a second story nozzle, heat and a long brush to break up the mold and it takes a while… Any suggestions or ways to improve? Thanks in advance!


Use the search, top right of your screen, scroll past store results to the community results:

“House wash mix”
“Down stream injector”


Is this a joke? Have you done no research at all? :flushed:


Use a big pressure washer and sodium hypochlorite. That’s the short answer.

The long answer could fill books. What is sodium hypochlorite? Where do you get sodium hypochlorite? How much sodium hypochlorite? How do you apply the sodium hypochlorite? How do you store sodium hypochlorite? How do you keep the sodium hypochlorite from running off? How do you rinse the sodium chlorite? How does the temperature affect the sodium hypochlorite. How do you prevent the sodium hypochlorite from killing the plants? What if it gets on aluminum? What if it gets on stained wood? Can it get on patio furniture cushions? What if the siding is oxidized?

You have to get busy reading. This forum has pretty much everything you need to know.


You know that this thread is going to be at the top of the search results for “Sodium Hypochlorite” from now on… :shushing_face:



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Use the red tip.

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Call a professional


Put sodium hypochlorite in you buffer tank. Usaully 50 SH 50 water. It will take it off in under a minute. Turn your heat all the way up to sanitize the house when you rinse. DONT use the red tip like @ChrisTripleC said you could damage the house… Shoot me a call if you wanna chat about the process anytime is fine (605) 475-6968


I don’t know guys…you’ve all given some very good advice but if you ask me the best way to tackle jobs like that is to use a strong chemical to kill of the algae/mold. My suggestion is Muriatic acid. Spray it on straight with a spray bottle and then use a wire brush to knock off the top layer so that the acid can get down to the stubborn stuff. It works like magic!


Hey, he’s read 13 min. Can’t expect him to do too much. :grinning:


The best way is to Hire a professional

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And this is how misinformation gets spread through the interwebs. No wonder I had such a difficult time learning the ‘right’ way to wash last year, it ends up in the search results!

Do a search, they say.
Use a red tip, they said.

Then I get IBS on my case for doing it incorrectly.



Sounds like it.


I wish we’d just start calling it what homeowners know it as. I can’t bring myself to say sodium hypochlorite to a customer. Feels kinda scammy and dishonest…


I always say “I use sodium hypochlorite in my soap solution, Sodium hypochlorite is a fancy way of saying bleach. If you are home you will probably smell a ‘bleachy’ smell about the same as being at a public swimming pool. It helps clean your home from all the green nasties, and the other soaps I use help to rinse the dirt off to leave your home clean and fresh”
I have done final walk arounds with customers and they say “It even SMELLS cleans”
I just smile.

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I say I use a proprietary custom blend to microscopical rid your home of unwanted organisms.

Jk, I say diluted bleach.

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Actually I’ve found homeowners are waiting for me to say ‘bleach’ when describing what the process is. I do point out it’s around a one percent strength though.

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I like the flux capacitor process myself.