My test roof experiment

So I’m back with pictures! Took @dcbrock advice on mixing and got the house wash mold issues resolved. Went back to my brothers roof which is around 15 yrs old and picked far back nasty corner to test 5% mix on stains. This is what I ended up with after the first 1.5% mixture that I thought was a 5. So it’s before after 1st,after2nd week in between and now after couple rains? Did I burn it does it need another spray or spray it to make it match​:grimacing::grimacing: ! Please and thank you! image|375x500

Before didn’t load I don’t think it’s more like what roof on right looks like to start with.

@Mrcus That looks better, did you mix 10% SH at half/half with water and add a thick surfactant?

Yes. 4gpm 12 volt pump and mix 50/50 with 10%SH &water and apple wash. My concern is with the second to last picture . From distance it looks almost brownish/white instead of the last pic of the newest shingles on the house. I did not rinse. Is it the age or did I mess up again.

If it’s black go back, if it’s brown it will come down.

So you think if I wash now more of the brown will come down? And how long do you think sh has to sit out before it loses it potency?

I had a roof I posted awhile back that turned brown and totally freaked me out. It took a HEAVY rainfall to finally come down, but the next day it looked gorgeous.

In the second to last pic, the stuff on the right will come down but it won’t be immediate. The stuff to the left needs to be hit again. Last pic needs to be hit again

Edit: the roof I posted most recently is one that I retreated, walked and rinsed. It took longer than I wanted it to. There’s another one somewhere on here that I left for the rain, came out just as good

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@Jake_Lambert thanks I’ll hit it again and maybe rinse on it and see how it goes!

If you rinse within 24 hours, make sure you know where the gutters are headed. Last thing you wanna do is fill a flowerbed full of SH. Japanese maples are pretty expensive


done another spot rinsed with garden hose then another application looks a lot better. Thanks for help guys.


you will want to get ladder stabilizers to avoid resting the ladder on the gutters.


I have one he’s gonna replace these gutters so wasn’t worried to much on it. Thanks though.

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