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How do I clean tannic acid stains on my patio?
Revision 1
2022‑06‑07 01:43
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How do I clean tannic acid stains on my patio?
2022‑06‑07 01:43
Active REV1
Initial text
We are currently building a patio roof. To protect the sidewalk from being stained by the painted beams, I put some wooden slats under them so they wouldn't lie directly on it.
Now for the positive: the paint didn't stain. The negative: one of the slats was oak and left an ugly streak on the sidewalk after it rained. There was no way I could explain it and I started googling... and here it is: the wood reacts with the lye of the concrete sidewalk and releases tannic acid, which leaves a rust-like residue.
Is there any way I can clean it again? Has anyone had any experience with this issue? Otherwise I will have to replace about 25 stones...