Surface cleaning

i did a job today cleaning a big driveway, it turned out great with minimal lines in the concrete. I DS’d on it after and it looks brand new. But i noticed when i cleaned it i made lines only when i came back on the concrete. whats the proper way to surface clean? Do you walking down and clean on the way back ( so both directions) or do you clean then bring it back and cleaning down again( just in one direction)?:confused:

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Good question Josh.

Concrete does not have a nap like a fabric or carpet would. The cleaner lines can be damage to the concrete or more likely just double cleaned . We often downstream detergent on the concrete after we wash it and let it set.

Thanks Tim,

I am still newer to surface cleaning only have dont about a dozen jobs and just want to make sure im doing it right. I have tried overlaping about 6", halfway and about a inch with same results just different width lines. How much overlap should i use?

My goal is no overlap. We get paid to wash a given area once. We are losing money when we double wash it. Overlap is a fact of life though. The smaller the overlap, the more difficult it is going to be to make good time. Pick the overlap that allows you to get done in a reasonable time.

Switching to a wider degree nozzle pattern may help also.

Are you sure your surface cleaner is the right size for your pressure washer? Are the nozzles on your surface cleaner matched to the GPM of your pressure washer? Are you pre-treating the concrete before you clean it? And if so, how much dwell time?

Also, I’ve had Surface cleaner nozzles wear out… I noticed when I first got my Mosmatic 24" it would hover about 18" off the ground if I kicked the side up… Then after a few months it wouldn’t do it anymore… I changed the tips to new ones (same size), and it shot off the ground again… Also cleaned better too…

Im usually use the 5.5 / 4000 machine with a 20" surface cleaner. they have 2502 im pretty sure. I did buy some 2503 but i dont think that are right and havent used them. The tips are the ones that came on it , its a hammerhead model. I have tried it with my 4gpm machine but its too much for it. as for pre-treats i dhavent been. Is there anything better to pretreat with other than SH.

Can you use a 40 degree? Im using a 25 now

I always pretreat concrete before cleaning, even if it’s just house wash mix. If it’s really moldy or has tree sap, I’ll boost the SH mixture to help. If there’s oil, I’ll pretreat with a degreaser. If there’s rust, I’ll pretreat with an acid. The chemical you use to pretreat is always dictated by what you’re cleaning. There’s not a one cleaner-does-all. Typically though, a SH mixture is what you’ll use the majority of the time.

Try using your surface cleaner WITHOUT the downstreamer installed. If you look closely at the inside of the downstreamer, you’ll see just how tiny of a orifice it has. While this may be fine for washing houses, it limits you when you’re cleaning concrete. I suggest using the downstreamer to apply your pretreatment cleaner to the concrete and then removing the downtreamer so you get optimal water flow. You’ll be surprised what kind of difference this can have.

If this doesn’t help, try using 1503’s and 1502’s. I agree with Guy that sometimes going to a wider spray pattern can help, but sometimes going to a narrower spray pattern can get surfaces 100% clean with the first pass, eliminating the stripping. Don’t go any narrower then a 15 degree spray pattern though, unless you want troubles.

I really think pretreating… allowing about a 10 minute dwell time… and removing the down streamer before using the surface cleaner will give totally different results.


Ok, Thanks Micah and Guy, i will just play with the nozzels to see what works for me.

Oh, and there is, on rare occasion, some concrete that just stripes. No matter how many times you go over it, it stripes. Many times this is due to tree sap. Hot water helps, but if you don’t have hot water, a strong SH mixture will eventually fade away the stripes.

There are pretty good cleaning chemicals like vinegar which can be used for cleaning. Take nice scrubber to clean the surface

What is SH? Trying to get used to the acronyms.

Sh = sodium hypochlorite. Which is chlorine bleach.


SH stands for Sodium Hypochlorite. SH is the key ingredient in house washing. It’s basically the same as the bleach that you put in with your underwear. I think the laundry bleach is 6%. Most guys on here use a stronger 12.5% version of it which they then mix with varying amounts of water. The stronger version can be a little harder to find. For a small quantity, go to a pool store and get a product called Liquid Shock. Same stuff.

Note that the 12.5% SH does not keep well. It loses its potency after a couple of weeks. Heat, sun, and contaminants make it go bad that much faster. Use it or lose it. If it has been sitting in a warehouse or on a shelf before you buy it, it may have already lost some of its potency before you buy it.


Thanks for the reminder about the shelf life of SH. I am debating between two suppliers for 12.5% SH. I contacted a pool supply store and they can get one gallon containers in a 4 gallon case for $6 each. I can also get 15 gallon containers from Univar (still waiting on price), but the minimum purchase price is $350. I would hate for it to sit too long and expire.

In which size does everyone typically purchase SH? I’m just starting out, so the stuff won’t exactly be flying off the shelf at first. Thanks in advance!

Where I live many pool supply stores have large (thousands of gallons) vats you can fill your tanks from. I operate in Florida where power washing is a big thing so I have no idea if this is normal or not.

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I found one way to help eliminate the striping is to go over twice, but only once in each direction when possible. As in N to S, then E to W. The striping occurs because when you push the SC the outer edges see the nozzle longer than other edges. Overlap just enhances it. The above comments are all great inputs also to try and reduce them.