Asphalt stained after pressure washing concrete

Hey folks. I work with a window cleaning company in Atlanta. A large portion of our business is also pressure washing and soft washing. We landed a large commercial job for a megachurch, pressure washing all their sidewalks and curbs. As you can see in the image, some runoff from the concrete has pretty badly stained the asphalt surrounding. The manager for the church has been very shady with us, and reluctantly told us after the fact that the asphalt was only a few months old and the sealant was a month old in some places.

We stopped in the middle of the job about halfway complete. The manager is refusing to pay us for the work completed and wants us to pay to reseal the entire affected area.

We’ve never seen this before, and have pressure washed around a lot of asphalt. The asphalt contractor we spoke to said he has never seen this before, and refused to take on the sealing job. He seemed to suspect that the quality of the sealant used previously was of an inferior quality and wouldn’t touch it. We attempted to use a surface cleaner on a small area of the affected asphalt, and this stain wouldnt come up. We didn’t use full pressure as we were hesitant to damage the asphalt any further.

We were pressure washing the concrete without any chemicals, 100% water.

Any ideas or opinions would be appreciated. Do you guys think that we’re liable for this? What could have caused this to happen?

I’ve seen that happen to some guys on YouTube, but it’s usually with a hot mix and new coating that was applied in the past 6 months.

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I usually soak blacktop prior to working just in case. That looks like it dried at some point. Keeping it wet usually works for me. That’s on newer sealed blacktop.

You’re with Window Genie?

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How old was the concrete?

We havent asked about the age of the comcrete but it was not brand new. It was well worn and definitely needed the pressure washing. I’d guess at least 2 years old.

It looks milky, like cream off the top of the concrete…never seen that other then newer concrete with too much pressure. Any marks in the concrete?


It’s almost certainly a concrete runoff, the puzzling thing is what was up with the asphalt to make it stick to the point where a pressure washer couldn’t really get it off.

Maybe with the sealer being new and with warm weather it warmed up the sealer to allow the runoff to settle in it a little? Not sure.


Best case scenario is one of those runs happen to look like jesus or something and they can call it a miracle and charge people 10 bucks to see jesus.


… i just want to clarify something.

You work for a window cleaning company.

You dont own the company, is this correct?

Any chance you have a before and after, and a close up of the cleaned sidewalk?

I’m no expert but like others mentioned I really feel the cream was blasted off and is currently running onto the asphalt. That would explain the light grey color, typically when concrete is done the runoff is a dark brown.

What pressure were you using in the surface cleaner?

I think is the wash off from the stucco walls, that dried on the cement and got washed off

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He didn’t wash the stucco, so still a mystery.

Got any more pics, including of the concrete? How old is concrete? I’m kind of new at this, how do you wash concrete w/o any soap or chems? Take it, it was recent and pretty hot that day on the asphalt?

I think he said ithe concrete was around 2 years old…asphalt was a couple months old.

Put some diesel on a test spot .
Diesel is actually not good for asphalt but lots and lots of guys have been using it for years to settle asphalt Millings
Im aware this is probably the worst advice I’ve ever given and if it was me it’s not the path I would take

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And Yes your :100: percent liable and I really have a hard time believing you used no chem including any soaps

He never said how much pressure he was using. Never the less, you can see from the one pic with curb in it, they just barely rinsed the concrete off (you can see the residue there) and didn’t chase it very far or dilute the runoff enough that on a hot day, ( heck even a cool day) even if it wasn’t whitish, it’s going to leave dirty water marks all the way to the drain. I see it all the time, these guys come in and bid commercial concrete cheap and don’t figure the time it takes to rinse properly. On a job like that the rinsing would have taken twice as long as the actual concrete cleaning, especially on asphalt which takes twice as long to rinse as concrete anyway. That runoff has dried into the asphalt now, going to be fun getting that all cleaned. And he’s surprised they don’t want to pay him.

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