Concrete Patio

Hi everyone! I’ve been looking for a pressure washing forum, looks like I found one finally. My names Jay & I run a power washing business up north. So yesterday I had to clean up a concrete patio (pool area) for a real estate agent selling the home, the pool area looked like it hadn’t been cleaned in 3+ years (easily). There was a huge difference between before and after but I wasn’t impressed with what I saw under the dirt and grime.

It surely does look like the homeowner in years past tried to power wash or hired someone to power wash and they damaged (?) the concrete. I use a surface cleaner, generally won’t bother to use my spray wand unless it’s a small area so I’d never leave a streak. Was not impressed at all once I un-covered this because I put in probably 3 1/2 - 4 hours into cleaning it. Now sometimes you’ll clean a surface and you’ll see what it actually looks like & that’s understandable but I was baffled at how bad someone botched this, when ever they did.

I’m not stuck with this job but for future reference, what’s your approach if you encountered this? Obviously this is a bit more involved since I already used a solution & cleaned the surface. It looks like someone sprayed too closely into the concrete with a high pressure at one point in time.

Crazy day!

Did you post treat? Even though there are wand marks it looks like it’s still dirty in those spots. Hit a small spot with some 6% a few times just to see. If that doesn’t work it is probably etched. Nothing much you can really do about that. You can try and blend it some with an acid but you’ll get mixed results.

Your best bet is to set expectations with the customer before cleaning. Sometimes you never know what you’re going to find under years of mildew and algae growth.

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Wait, you spent four hours on that?

Yup, I mean look at the before, it was dirty dirty… thats years of not cleaning. I usually assess almost every project I book, this agent called me Wednesday asking to get it done asap, rained Thursday Friday, so I didn’t see it until I got there Saturday.
I prep the surface too, I let my solution sit for 5-10 minutes (soaks up) then I get on it with the surface cleaner and I’m fairly tedious… could not believe the outcome.

No post treatment, I was given a tight window from a real estate agent so didn’t have the usual options for this, 9 times out of 10 I don’t have to do a post treat. I had my wand on top of a couple spots and absolutely nothing changed. Maybe just maybe if I used some type of concentrate to brighten it, maybe it would look “better.” I’ve only done one other property where lines or patterns were left from improper power washing. Unreal man, I woke up today still bothred about it, I take pictures & record every job I do, I’m proud of my work.
This was a curve ball!

You can’t leave that like that. Call a professional contractor in your area and pay him to do it. Post treatment takes about 1 minute. How tight of a window did you have?


A lot of times post treatment is a necessity. It can make a bigger difference than pre-treating. I think you’d be surprised if you hit it with 3-4%. Do a small test area with straight SH just to see. I still think the wand marks are just from the lack a cleaning a nozzle can do on concrete.


What size surface cleaner do you use and what size machine? Maybe it’s just me but those “wand” Marks look really straight and could be a super small surface cleaner like those little 6" ryobi ones

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15” surface cleaner & 3300PSI 2.5GPM —- I was double checking as I went. Usually If I streak or don’t cover ground I’ll see circles or just small bits unwashed. Not sure who or what originally power washed this property. I don’t generally use the wand to power wash patios, only small areas or spots my surface cleaner can’t reach.

Thanks for the response, I will try this out next time I have a patio to do. I usually treat immediately

Somethin seems a lil fishy…


It’s pretty wild to me that you can’t see any striping in the spot where the deck umbrella was (kind of a square clean spot) in the first picture. But then stripes appear in the after pic

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Honestly my man, I don’t feel like you “uncovered” this. It really seems like you caused this. Either way, it’s still not clean


Those are surface cleaner stripes not wand stripes. Could have been a homeowner job I guess…


Disagree how do you explain those straight lines, I didn’t use my wand

Lines are from surface cleaner overlap. Needs to be post treated. Also, if you’re doing this to make a living do yourself a favor and invest in some professional equipment. Pull up to pull out including post treating in an hour or less.

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I would genuinely be disappointed in myself if it took that long. Of course, 8gpm lets you move pretty fast but even with a smaller machine that’s a 40 minute job. Heck, it would probably take me as long to set up as it would to actually clean it lol

Nailed it. Somebody went crazy with the SC…

You’re using less than four GPM machine which is like… bare minimum that you should use and call yourself a professional. 5.5 is a better place to start. Those lines are there from your surface cleaner but also because you’re moving way too fast that’s why the middle is dirty and the sides are clean(stripping effect). You have a homeowner machine and a professional machine is needed to do a professional job… so if I was you I would take some money out of the savings and invest in some real equipment real fast. For now hire a real professional to clean the mess you left and watch him so you can learn