Soft washing roof

So I’ve built myself a setup with 5.3 pump ,15 gallon tank and 25’ of hose all a garden wagon.
I’m trying to practice on my on house ,but my mix of 10% bleach at 6 gallons to 9gallons water with 6 ounces of gain is leaving patches of black spots . SURELY MY mix is strong enough, am I just not getting good coverage ? It’s not sudsing up so its hard to see my coverage from a latter. Any help would be greatly appreciated. Thanks Allen

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Try mixing 5 gallons sh to 6 gallons of water. A15 gallon tank isn’t near big enough

@AWM What strength SH are you using? Not sure how your mix is 10%

Bleach is 10% . Mix should be about 4%, Right ?

3 to 4 %

Ok I read your post wrong but yes that is correct. Ok what kind of roof are you trying to clean? Shingle? Tile?

That’s another question I had ,it’s a 2000 sq. Ranch how much mix will it take ?10gallons per side ?
I was planning on mixing another batch during the 10 to 15 min set time.


@AWM If what you tried isn’t working i would suggest making sure you have fresh bleach and maybe try a stronger mix. Not sure where you live but if you are trying this in colder temps the SH isn’t as effective. I would also recommend a commercial grade professional soap. I don’t have experience with gain but maybe use more if you aren’t getting a thick mix. Trial and error.

Thanks . I’m testing everying on my house first ,before I move on to others.

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If you have real dark spots, even with a 4% mix, sometimes you have to hit more than once or twice. How steep is your roof? The steeper, the more important it is to have a good surfactant. You should be able to see the stains remaining in about 5 minutes. Just reshoot them. If glare is bad, I always take a pic of roof on phone before I get up on ladder so you can look at and see where real bad spots were if you can’t see them once you’r up on ladder or have your ground person spot them for you.

It’s easier to just wait on ladder for results than to go back down and up again. A steeper pitch roof just figure you’re going to cover about 50 sq ft of roof per gal of mix. As you get more experienced will come down some, but not that much using 10%SH. The more you practice the better you’ll get.

I’ve had some really bad spots take 3-4 hits even at 50%.


Thanks Racer you were spot on about everything .


We like to use the Pro Mix Alot or ProProportioner for this issue. I’ve been exactly where you are, and when you mix too much water in a batch mix and the roof is real hearty moss, you can’t go back unfortunately. You can always leave the mix up there, and come back a month later. We just like proportioning hot, 75% SH 25% water and batch mix our surfactant into the SH. It always works the first time, everytime. Good luck.