Colored, stamped concrete cleaning

Hi all, I’ve been searching for a couple of hours now but can’t find the info I’m looking for. I’m estimating a house right now and the one part I’m worried about is a stamped concrete walkway, about 200’ long with lots of organics. The owner swears her husband has pw’d it multiple times, and that the concrete itself is colored. But from some of my pics I think it’s a surface-stain that was applied, and it looks like it’s starting to show some aggregate. The finish does not seem like paint, and is not flaking anywhere. But around the cracks I can see the actual color of the concrete.

I was thinking of a 2% pretreat, and dropping my SC down to about 2500 psi or even a touch lower. I’d love it if a pro could weigh in and let me know what they’re thinking on this one, I haven’t seen it before.

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Here’s a couple more; it’s definitely colored intentionally, the grey isn’t just organics.

Should handle the 2% fine, but not even sure you need that strong, doesn’t look all that bad. I’d go a little lower on SC psi, maybe around 2000.


Ok, so interestingly enough I am wrapping up a commercial job that has pretty much exactly the same thing as your pictures. I wasn’t the one in the end to clean it as I hurt my back so I had to call in another company due to timelines. After they finished some of the color was lighter, so I believe you are correct in thinking its a surface stain. I personally would use more in the 1500 psi range with a 2-3% pretreat and give it some good soak time to hopefully avoid taking off less of the stain, but I’m so green at this that could be terrible advice. I wonder what others will say.

Edit-I have no idea the pressure that they used. Im guessing 2500+.

I soft wash those…

HW mix

May not be useful information and I haven’t done stamped concrete myself but I’ve heard about it a bit.
From what I’ve seen, guys that do stamped concrete get regular concrete in and then cast colour oxides over the pad to create a natural colour palette. That’s why the colour is only on the surface and not through the entire pad. They can create custom colours that mimic natural stones and the like.
Whereas with a concrete mix that has oxide mixed through it is one uniform colour all the way to the ground. Doesn’t look very natural and isn’t as customised, but would be a lot cheaper than stamped concrete and can still look great with the right crew

The splotchy color is the sealer fading… Once they stamp the concrete pattern, they add a powder dye, then sealer. I know, cause we poured our own patio with a stamp, color, & solvent sealer 8 years ago. Use HW mix, medium pressure

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@Oakley How have you found the concrete to be holding up? One of my old bosses said a problem that can come up is because of the stamp lines, it can create stress points and encourage cracking. Have you found that to be the case personally?

No cracking. We laid rebar about 6 in. deep, trowel it good! then pattern stamped it! The sealer just fades over time & needs to be resealed.

Make sure the control joints are spaced even too

@Oakley Awesome. I’ve always wanted to try it but haven’t had the chance. His reasoning behind it was that it creates stress points in the concrete because of the impression lines and encourage cracking.
Obviously the steps you’ve taken have prevented that and still have a great looking pad years later! I wouldn’t mind pics in PM if you’d like to share :+1:t2:

To be fair, there may be surface cracking with cheap sealers. But it doesn’t hurt the foundation structure, just surface expansion. Top layer is the softest. The patio will be cleaned this coming weekend, I’ll pm pics for ya.

Great. I’m still passionate about great looking jobs, even though I’m over doing the work lol

I learned the hard way a couple years ago. This client had an “integral mix” concrete, which meant that it the color was mixed into it before it was poured. Theoretically you could drill a hole through it and it would all be the same color underneath. So we surface cleaned it with a 4 nozzle sc at 2800. Was looking good until it dried, and then most of the color came out. I consulted with a stone specialist who educated me that while it can be an integral mix, there is usually more color added on the creme coat on top. Don’t use pressure, or if you do, go low, test an area and let dry before you do the rest. There is obviously different products and applications but at least don’t make the mistake I did and think it’s good because it looks good wet. I will only softwash colored concrete with roof mix and brush now.

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This is a stained sidewalk that I have washed several times. The first time I used 1% sh and it worked good, but a lot of pedestrians made faces at me. So, the second time I downstreamed straight simple green. The simple green worked really good! No organics on it tho.

Looks like good, ole fashion concrete with saw cuts.


Maybe stained with dirt. :smile: I don’t see any coloring at all.


What they wondered why it smelled clean? Care less what they think do what you know is right and stand by it. I get compliments on the bleach smell


It’s a gray stain. There are chips where you can see the natural color.