Removing stains from stone or cement

[Bob Weisner]

Hi:

I was at my sister's house yesterday for a party they were having. They had just had a new walkway put in for the backyard patio a few days before the party. I don't know if the patio was made out of that stamped concrete or if it was real stone. What happened was that the contractor that put the patio in had colored the stone/stamped concrete and when he went to hose down the walkway, the colorant had bled out . Now there are stains in the walkway that the contractor cannot get out. They have soaked into the walkway. They tried Muriatic acid, but that did not work. This walkway really looks BAD! :( Is there anyway to correct the problem? I though about grinding the colorant out, but that might make a bad job just look worse. The contractor says there is nothing he can do. Any suggestions?

Thanks,

[Norman Hitt]

Maybe another stain to cover or camaflague that area followed by a sealant? If not, maybe the contr. will just have to take out the part he ruined, and replace it.

[Ken Garlock]

Bob, give good old Clorox a try. Last week, I kicked over a bottle of the purple primer that is used on PVC pipe right on the concrete sidewalk. :mad: After a few comments regarding my agility, I figured I had nothing to loose by pouring straight Clorox on the the stain. I let it set for about 5 minutes while keeping it wet. A good scrub brushing, and the stain was gone. While it was wet, you could see the outline of the spill, but the next day, you could not tell that anything had happened. :)

Some times even I get lucky :o

[Frank Hagan]

Muriatic acid will just etch the surface, but won't really remove a stain. Try household bleach first, then step up to liquid swimming pool chlorine (a stronger solution at 9 or 11% ... whereas household bleach is 5%). Do NOT use granular "shock" chlorine (calcium hypochlorite) as it can explode if exposed to dirt.
The next thing to try would be "deck cleaner" or wood bleach from Lowes or Home Depot. It is oxalic acid, and can work on some stains that household bleach will not. Finally, hydrogen peroxide may also whiten it.

[Randy Meijer]

What about using one of those HP washers??