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I have noticed that many trying to clean cedar haven't considered the factor of tannin.

Cedar is among a group of woods ( like Cyprus, Redwood and Mahogany) that have a natural acidic chemical called tannin which is caused by moisture in the wood. Tannin is water-soluble.

Here is a cedar roof we just cleaned that had a lot of tannin, combined with brown rot fungi and other infestations. What many miss is the proper cleaning of tannin and when the roof dries from a cleaning it will look like a checker board. On a cedar roof the tannin will have a black look to it. In most cases some section will have it and some won't because of the moisture content of the cedar roof.


When cleaning cedar roofs always consider tannin and the removal of for the best results.

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Oxcilac acid right?

That will work, though I don't use it myself, I use a citrus base in my solution.

Oxcilac acid is caustic and takes pressure to properly remove. One word of advice, don't tell any cedar shakes home owner you use pressure of any form.

They are not that well educated to cleaning but they know pressure is potentially bad for a cedar/wood roof.

I have cleaned hundreds of cedar roofs and cannot tell you how many times they ask to make sure I don't use any form of pressure.

As to tannin, what happens when tannin isn't properly removed when the roof dries real well the tannin areas will darken again and the roof will look like a checker board.

Granted when first cleaned that day and a few days later they look nice but go back a week late and look and you'll see what I mean.

TSP works okay but it is tricky figuring out the amount to use for any given cedar roof because each roof is different.

Though we promote our service as away to extend the lifespan of a cedar roof, most home owners will always focus on the look. They don't like the checker board look.

Because some cleaners don't remove tannin properly, the results will be the checker board look and the home owner doesn't like that and won't refer your service

for that reason. Been there done that. LOL

One thing about a cedar roof that is different from all other roof material is that cedar "has" to be maintained to reach it's potential lifespan.

there is plenty of research about maintaining cedar roofs, unlike other roofing material where there is no or very little research that indicates the need to be maintained.

Thus the service sells itself once the home owner is educated.

Now the task is how to properly maintain/clean them. There are many opinions on that and can be debated but in the end is the customer happy with the results.

The reason I even brought this subject up is I have had home owners contact me after someone else cleaned their cedar roof and they wanted to know why their roof had that checker board look.

I explained that the cleaner didn't remove all the tannin, which is the case, but also explained that the look doesn't effect the cleaning results.

Anyway, to answer your question yes you can use it as it is a brightener but it is hard to work with. Been there done that also. LOL

I have developed a different solution I use and cleaning process. That will be shared with those that take me up on my cedar roof cleaning process.

FYI. With cedar roof cleaning the hardest to "remove" is lichen, tanning, brown rot fungi and moss in that order, which are your common infestations on a cedar roof.

Tannin being the one that many overlook and don't understand, which again is more towards the looks/results, but that is where your customer "will" focus, the results.

Your referrals will come from the results and if a week later, once completely dried real well or after a good rain, it has a checker board look you lessen your chance

of getting their referral. We all know referrals are key, more so, with cedar roofs.

Cedar roof home owners tend to be higher end homes, professional people and get it once they have reviewed the research. They won't let just anybody near their cedar roof.

They also are great candidates for other services when cleaning their cedar roof i.e. house wash, deck cleaning, gutter cleaning, driveways etc.

I personally don't promote such, though I could, but for those that offer such also it is a no brainer.

I know I have rambled here but also want to see other cleaners to approach such professionally and make some serious income. It is all in the results.

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Bruce- Being a painter I know if you put latex paint on cedar the tannins bleed through( from the water in the paint), Isn't the first rain on the cleaned cedar roof going to bring out the tannins again? Or is it that the whole roof would take on the tannins evenly therefore eliminating the checkerboard look?

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