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  1. #1
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    Feb 2008
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    Default Recommended Chemicals for Powerwashing?

    Hello, all. I would like to remove longstanding dirt and moss from a brick walkway and a cement sidewalk. I know I have to use the powerwasher carefully so as not to crack the surface, especially the bricks. Is there a recommended chemical treatment which will help speed along the process? If so, it MUST be able to drain onto grassy areas without killing the grass.

    Thank you very much.

    Dan

  2. #2
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    Aug 2007
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    Default Re: Recommended Chemicals for Powerwashing?

    The pressure washer alone should do the trick, even a low pressured one. If the brick is mortar set and grouted, then you won't need to be too careful, other than not to use extreme pressure. If the brick is set on a compacted base with no grout or sand filled then pressure washing is going to disturb all that and you'd be better off going about it with a scrub brush. Either way, chemicals should not be needed to do the job.

    Once it's been cleaned, periodic spraying with hydrogen peroxide will help to keep algae at bay.

  3. #3
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    Thumbs up Re: Recommended Chemicals for Powerwashing?

    I live in New York and it is cold right now so I have to worrie about snow not moss but I will give it a try. In the past I have just washed off the surface with a pressure washer and then gone to a product called JoMax. I purchased it at Lowes and you mix it with bleach and hot water. They also sell bleace that is foe the purpose of outdoor use. It has a mold and mildew killers in it so it works double duty. DO NOT put it through the pressure washer! It will destroy the seals inside the pressure washer.I have used it on my house and on my sidewalks, and it does a great job. After it has dried you should seal the brick and concrete with a sealer. I recommend using a paint roller with a 3/4 nap roller sleeve on it so you get good coverage. If it has never been sealed you should let it dry and seal it twice. Follow the instructions on the label for the product that you are using. Keep in mind if you use a high gloss sealer, it will make the surface slippery when wet. Hope this helped with your problem..

  4. #4
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    Feb 2008
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    Default Re: Recommended Chemicals for Powerwashing?

    Thanks for the advice. I live outside Philly, where it's quite cold now, but we are making settlemnt on a home in April. It appears that the surfaces have not been cleaned in years, if ever. I was hoping to not have to scrub by hand; thus, the powerwasher. I wonder if Simple Green would work with light brushing (heavy duty broom) followed by the power washer? Further, I never knew that you have to seal brick!

  5. #5
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    Aug 2007
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    Default Re: Recommended Chemicals for Powerwashing?

    Dank,
    It sounds like you've never used a powerwasher. That's OK, we're all virgins at some point. Like Spruce said a power washer will take off almost everything including the skin on your hand without chemicals. Dirt & mildew on brick & concrete is generally no problem.
    Sealers on brick may or may not be called for. One train of thought is that they can trap moisure & cause spalling with freeze/ thaw cycles. On the other hand, my uncle lived in a highrise that had water penentration problems that seemed to be solved by a sealer applied to the brick.

  6. #6
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    Feb 2008
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    Default Re: Recommended Chemicals for Powerwashing?

    No, I have used power washers, and I own one. My concern is the amount of pressure. I thought that if I used some type of solution, it would loosen the dirt, so that I could ease up on the PW's pressure.

  7. #7
    Join Date
    Nov 2007
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    980

    Default Re: Recommended Chemicals for Powerwashing?

    down here in florida we get a lot of mildew on the top of our green houses and what we do is with your pressure washer you should have a chemical tip (usually the black one if they are color coded) and we simply run a bleach solution on, let it sit for a while the pressure wash it off. we have done our walk ways the same way.

  8. #8
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    Aug 2007
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    Default Re: Recommended Chemicals for Powerwashing?

    Quote Originally Posted by havanagranite View Post
    down here in florida we get a lot of mildew on the top of our green houses and what we do is with your pressure washer you should have a chemical tip (usually the black one if they are color coded) and we simply run a bleach solution on, let it sit for a while the pressure wash it off. we have done our walk ways the same way.
    I still say that pressure washing alone - without the use of chemicals - is the best course of action, at least to start with. My patio gets green with algae during the winter months, simply washing it down does the trick. If I feel like it I'll sprinkle a little peroxide over it after the washing which helps to kill any remaining algae and lengthen the amount of time before it regrows and requires pressure washing again. No chemicals to harm grass, animals or the environment.

    My recommendation to a first time user of a pressure washer is to dial the pressure all the way down and use the largest orifice tip you've got, then adjust the pressure and tip selection until you're getting the dirt and algae off without causing undue damage. A portion of my walkway used to be a combination of concrete, concrete pavers, and recycled brick. The pressure washer did no damage, though it does an excellent job of blasting the dirt out from between things (that you don't necessarily want removed). Just use care and caution, work slowly until you get the right pressure, tip, angle of attack, and distance from your work.

  9. #9
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    Feb 2008
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    Default Re: Recommended Chemicals for Powerwashing?

    Quote Originally Posted by A. Spruce View Post
    My recommendation to a first time user of a pressure washer is to dial the pressure all the way down and use the largest orifice tip you've got, then adjust the pressure and tip selection until you're getting the dirt and algae off without causing undue damage. A portion of my walkway used to be a combination of concrete, concrete pavers, and recycled brick. The pressure washer did no damage, though it does an excellent job of blasting the dirt out from between things (that you don't necessarily want removed). Just use care and caution, work slowly until you get the right pressure, tip, angle of attack, and distance from your work.
    Good advice; That's it. Thank you all for your input.

    Dan

  10. #10
    Join Date
    Aug 2007
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    6,481

    Default Re: Recommended Chemicals for Powerwashing?

    You're welcome.

    One last tidbit of advice, you'll want to wear eye protection of some sort. Blasting irregular surfaces has a tendency to direct debris and water directly into your face.

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