One thought on “What are the black stains on my deck and how do I get rid of them?

  1. Arti says:

    Pressure wahing will work although one has to be careful to not raise the grain with the force of the water. There are many products on the market that will take off the stain. When it comes in contact with any metal, a black stain will form. it’s called Jomax stain, mold and mildew remover for decks. One of the better products we have found is made by Zinsser. it’s a product that , when sprayed on out of a spray bottle, will immediatley take away the stains. Oxalic Acid, mixed with water will work. Tannic Acid is contained the lumber. The black stains on Redwood are caused by the very thing that makes Redwood resistant to bugs. In addition , over time, Redwood will trun a grayish color because of Tannic Acid.

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