Roof chem alternatives

kdfoust

New Member
Hi:

I did a couple of test patches on a painted concrete tile roof that is heavily molded. The main goal was to remove the mold, mildew and lichens. These roofs had never been cleaned before. Here is what I tried:
1. 10% sodium hypochlorite straight out of the sprayer.
2. 10% sodium hypochlorite through down stream injector (1:16 ratio).
3. 10% sodium hypochlorite (1:16 ratio), 10 minutes dwell, hit with a 1515 nozzle.
4. I also tried my surface cleaner with a 2520 nozzle.

Basically, none of these tests produced real good results:
The NaOCl, even at 1:16, caused pretty significant fading and red runoff.
The surface cleaner cleaned the high spots and removed paint while leaving the troughs on the shingles still ugly.
The best results were obtained using the 1515 nozzle after appling NaOCl. I was also able to remove the mold with the 1515 with no NaOCl, however, it took a lot longer and much care has to be taken to not remove paint.

Okay, are you bored yet? The reason I put all this up is that I'm looking for another alterantive to try other than NaOCl (sodium hypochorite). Is something like new-again worth messing with? Or how about oxygenated-bleach (Disodium Peroxydicarbonate)?

I'm planning to write a proposal for this client, however, I'd like have one more chemical option to try before I write the proposal. This may become a prep for painting project for my client, but, I'd like to make sure I haven't overlooked an option.

Thanks for any suggestions!

Have fun,
Kevin
 
H

hotwaterwisard

Guest
I'll email you my fungas list of interesting sites. Have fun.

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Hotwaterwizard@aol.com John DeRosa
 

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