Retaining Wall Cleaning


Well-known member
Jan 6, 2014
Dallas, TX
Is there a TPF type method for cleaning retaining walls and flagstone?

I have a power washer and could use simple green or bleach but I'm hoping there is some magic formula like sodium bicarbonate and vinegar!

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TFP Expert
LifeTime Supporter
Jun 7, 2011
Midland TX
Those two things will react and neutralize each other. Is it the Green you are trying to remove? If so, I would soak with diluted bleach to kill it, then and rinse/powerwash it off.


TFP Expert
Platinum Supporter
May 23, 2015
Tucson, AZ
Oxyclean is a mixture of sodium percarbonate, sodium carbonate and some perfumes/etc. The percarbonate supplies the peroxide which is a bleaching/oxidizing agent and will definitely kill that moss (chlorine bleach works better). But here's the's going to grow back. You need to kill it really good (*cough* *cough* bleach! *cough* *cough*) and then, you need to seal the stone. If you don't seal the stone, the moss will simply grow back again. But, as long as you don't mind the annual cleaning, you can leave it as-is....

*cough* *cough* ... use bleach .... *cough* *cough* .... dang pollen allergies.....