Yellow Residue on New (Not even a year old) Concrete

Why does the concrete look like this? Is there anyway to fix it? It had red clay before but after pressure washed it stayed like this. Any help?

I’m gonna guess the finish was messed up by pressure washing it so soon. Either that or it could be a poor job originally. @gbattle thoughts?

Try some f9 barc. I’m guessing residual stains from the red clay.

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Oh lawd.

That’s a terrible picture. I can’t see anything.

You shouldn’t power wash concrete within a year of being poured.

I do it frequently. I’m no concrete expert but if they poured the slab correctly it’s cured in a month or two. I see slabs several years old with soft cream and slabs two months old hard as can be. If I’m ever in the market for concrete I’ll be doing some diligent researching on who does it right. Whatever that may be.


How did you clean it?

I dont see any signs of either a surface cleaner or wand was used.

You need to give more info before getting answers.

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Was this area used to store the clay before spreading? If so…use

6-8 oz oxalic acid to 1 gal water (mix with warm water)
Pour solution into a pump up sprayer
Wet down concrete surface…then let the slab soak in the water. Now, apply the mix starting at the control joint to the right of the provided photo. Let it dwell for 3-5 min, then lightly mist surface with water! and brush solution around…after agitating, rinse the concrete.

Note: No Pressure Washer Needed

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?? Is this bad?

With wand and this acid cleaner called “mud away” from my chemical store

With which nozzle and how much pressure?

What kind of acid? You probably ate the top coating off of it. Brush it down with 12.5 and leave it overnight you might get lucky

40 degree and 2500 psi

Its some acid called “mud away” from my local chemical store, and that didnt take it off so i applied a light coat of muriatic acid w/ water

IF You go to do SC work at the Baptist seminary on gentilly blvd in New Orleans @Harold , Be careful ! there was a Super Weird nut pouring and finishing
All the new concrete there. Several Thousands of yards, could cream up at any time !! :crazy_face:

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Mayne I recon I should stay away from those parts. :joy: appreciate the warning

Sure looks like a nut to me…

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