Working at high-end home that is only three years old and the client has planter boxes made of stone that have some areas have gone from its typical light gray color to dark black. Upon close inspection, I noticed that there was a black grout line around the perimeter where the top cap meets the sidewalls. Somehow the color has leaked from the grout so bad that it is nearly completely covered the light gray walls on some sides in almost all black color. I tried using some F9 barc and Efflo on it full strength, but it did nothing. Is there an alternative product that might remove this coloring?
Also, there are some stone tiles that have random areas that are also colored very dark. These are isolated areas next to the same exact stone. See last 4 pictures for reference.
I did try Pressure with high heat, but did not try SH. It is not an organic stain, but color that leaked from the grout. The longer I do this, the more I realize that some things are just not restorable. I recently started putting notes in my estimate on large jobs about oxidation on the siding. Cleaning a huge stucco building can definitely get clean, but it might have discoloration where the oxidation is disturbed and it is not. I’ve tried BC cleansol in a high concentration but sometimes, especially on stucco, you just can’t really get it all out evenly. I know this post is not about oxidation, but explaining that some things need to be repainted or refinished, depending on the surface.
