Brandon,

Does this have a seal on it? I would do the normal ratio if there is no seal on it. I would bring a little wire brush with me and brush under the shingles to knock off the big stuff. Rinse rinse and rinse.

Brandon Vaughn wrote:

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This is a pretty common sight in the NW - Cedar shake roof that is covered in moss, lichens and nasties.

We get a lot of rain, but not very hard rain. So usually moss takes about 6 months to weather off of asphalt shingle roofs once treated.

Just curious how you guys would tackle something like this?

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 Gota say I am loving the new bulk rinse pump for follow up trips and retreats.

AC

I shudder at the thought of brushing each shingle with a wire brush! I think I'll bust out the cannon... Thanks for my booster pump's new nickname Zach. 

I sold this job and will be doing it next week some time. I'll post some after pics.

Brandon, I hope you can clean this roof without walking on it. The older cedar shakes get, the more brittle they become.

As you mentioned, it's old. Take your time and be careful.

I need some advise ...

The bottom photo is the northside of the home.  It had a lot of moss and mold. 

As you can see I can't get rid of the black mold.

I am using 3%, 50/50 blend of Green Wash and Terra.

AND

A lot of rinsing. 

Can anyone give me advise?  I'm right in the middle of the project.

Thanks,

Bob

 

The black that looks almost like paint is tanin. You never really get it all out completely. Also the north sided takes longer to dry so it still looks like crap when wet. As it dries it will lighten in color.
It will even out as it weathers. You are not restoring cedar, but cleaning. We are killing and and washing much of the fungus. It will weather to a grey color. A lot of what is left will wash off as the organics decompose.