New patio concrete damaged by powerwasher

by James
(Ontario, Canada)


Q. I just had some new cement poured for a patio area. Not knowing any better I cleaned the area off with a power washer a few days after it was set. After a short time I noticed black lines where I had washed and realized it was from the stream of water.

I quickly stopped using the PW but now I am extremely concerned about the lines. I just spent a lot of money to have this done and I am hoping there is a way I can fix this!

The cement itself is white with a broomed circular finish. Is there anything I can use to fill in the black marks this has created?

I have been looking around everywhere and all I can find is products to repair cracks or severely damaged areas.

I don't want to go and make anything worse so it's time to ask someone who knows what their doing.

Any help you could provide would be greatly appreciated.

Thank you!


A. Although you did not go into detail how deep the black lines are, I'm assuming you removed approximately 1/8 to 1/4 inch of the surface material. You can buy a bag of white cement and a bag of Rapid Set Cement All, mix them together at a ratio or 1:1 and patch the areas as per directions on the bag of Cement All. Broom the patched areas shortly after applying the patch material as it will dry very fast. This patch will turn white when it drys but will not completely match your existing patio. No material you use to patch the concrete patio will make the lines invisible.

The only way to make your concrete patio look like new again is to do a 1/4 to 3/8 inch overlay over the entire area.

I would recommend hiring a professional to either patch the lines or overlay the whole patio. Fixing concrete correctly is an art best left to experienced concrete repair specialist.

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