Whats the best pretreatment chemical to be used on decks before pressure wash?

Discussion in 'Power Washing' started by TooMuchClay, May 2, 2012.

  1. TooMuchClay

    TooMuchClay LawnSite Member
    from DE
    Messages: 80

    I dont do a lot of pressure washing but I was doing 3 houses back to back 2 weeks ago, and when I got there(by myself) there were 3 guys right across the street doing this one house. So I unload the 8hp Honda powered pressure washer I rented from Home Depot, and went to start the pretreatment with bleach by dropping the included soap hose into the bleach bottle, then I turned it on and climbed up to the top of the garage to do the 2nd floor siding over the garage. In the mean time, the guys across the street had already started.

    So I quickly discover that the soap hose isnt working, and isnt sucking out any bleach, so I unhook it. Then I grab my 4 gallon backpack sprayer, clean it out, and mix about 2 gal of bleach with 2 gallons of water, then I go and soak the siding with bleach. While I'm doing it, I can see all the dark green and brown dirt and moss just disappearing from the siding!

    So after soaking with bleach, I turn on the pressure washer, but by that time, all I had to do was just rinse it off cause the bleach had done all the work!:clapping:

    So I had to do the 1st and 2nd floor sides on 3 houses, and yet I got done doing all 3 houses by the time the other guys across the street finished doing that 1 house!:dancing:

    It wasnt because I'm the world's best pressure washing guy or anything, it was because I pretreated my 3 houses with industrial bleach mixed with water, which actually ended up doing 95% of the work for me! But the 3 other guys werent using bleach, so they had to spend all this time slowly running the wand over each little area while holding the nozzle only about 4" away from the siding.

    Now, bleach works real good for siding, but now I've gotta do 2 decks at those same houses, then I gotta seal them with clear, 4 year sealant. But bleach isnt the right chemical for that job, and I dont what is......

    There's something else that is supposed to be used on wood decks to clean them, and I believe there's even another chemical that will actually draw out the old stain from the deck surface. I dont think I need that, as the decks arent stained with dark stain or paint, and I think they have just been repeatedly sealed with clear sealant, so thats what I need to use after they are cleaned.

    But whats the chemical that I'm supposed to use on decks to help clean them?:confused:
  2. rlitman

    rlitman LawnSite Bronze Member
    Messages: 1,741

    Is TSP what you're asking about?
    That used to be trisodium phosphate, but because of what the phosphate runoff does to waterways, it is now sodium metasilicate. Either way, do NOT let this stuff dry on a surface. It can etch glass, and haze paint, but it is one seriously powerful cleaner, AND is even safe to be mixed with bleach for a 1-2 punch.

    Oxyclean is a good alternative to bleach.

    Those suction soap hoses just about always clog up. A tiny little bit of soap gets in there, dries up, and it doesn't work any more. You can take the hose off, and try to blow the barb out with compressed air, or try to pour some water in there to dissolve the soap, and they usually gets them working for me, but if you're applying chemicals, a pump sprayer may just be the easier solution.
  3. TooMuchClay

    TooMuchClay LawnSite Member
    from DE
    Messages: 80

    Since I also do mostly landscaping, I realize that bleach and other chemicals are terrible for plants, so before and after I used the bleach, I spray the plants around the area with water to wet them, then when I'm done the cleaning, I rinse off the plants again.

    I bought some TSP a few years ago, and it still was trisodium phosphate, and I think I still have the box around somewhere, but maybe its best not to use it since it has the phosphate in it. I was wondering if that was the right chemical but I wasnt sure. I guess you'd need to soak the nearby plants down and rinse them off when using that stuff too...
  4. rlitman

    rlitman LawnSite Bronze Member
    Messages: 1,741

    The issue with phosphate wasn't in harming plants, but that it would reach waterways as runoff (and through sewer systems) and act as a fertilizer for algae, which would bloom, killing fish. That's why it is being banned in dish washing detergent.

    Bleach shouldn't be that terrible for plants (in limited amounts). Your spray down before and after sounds like you're doing exactly the right thing.

    The same treatment with TSP should be good. My concern with TSP hitting plant leaves, is that it could dissolve the waxy cuticle that protect the leaves from disease and prevents dessication. It is a detergent after all.

    If you're using TSP anywhere near a car, or windows, you should do the spray down before and after on these too, or risk leaving behind permanent waters pots.

    Your use of a backpack sprayer was right on, but remember that if you're spraying bleach, any overspray/mist that hits your clothing will start it's way eating through it. If you're not wearing a tyvek suit, you may find a pile of rags the next time your clothes come out of the wash.
    Oxy-clean is relatively inexpensive, works about as well as bleach, and won't ruin your clothes. Oh, and it is also the correct chemical to use to kill moss growing on asphalt roof shingles (just do NOT use the pressure washer there, just use the backpack sprayer).
    Last edited: May 3, 2012
  5. lkendall

    lkendall LawnSite Member
    Messages: 157

    Also, bleach isn't supposed to be run through the pressure washer soap hose(But since its a rental its not your problem) also, if you are going to continue using your backpack sprayer you will need to get one with bleach safe seal (viton seals) or else one time it might be running down your back. Bleach works on deck, bleach mix before, pressure wash, then use a wood brightener on it after and you will be impressed with the result
  6. TooMuchClay

    TooMuchClay LawnSite Member
    from DE
    Messages: 80

    Well, my job for today cancleed, so I'll be working this weekend....

    They have even removed phosphorous from many/most lawn fertilizer now as well. In fact, when I was still working at Lawn Doctor in the mid 90's, we began cutting phosphorous out of fertilizer's used in spring, but still put a little down in fall.

    I use Oxy Clean(or usually the generic brand of it) for other home tasks, but I wasnt aware that it would do a good job of either cleaning moss, algae, mildew from shingles or siding or walks, but I was even less aware that it would actually kill the moss/algae/mildew....

    Oxy-clean is just primarily Hydrogen Peroxide, which has been used as a bleach substitute for eons. Plus, it doesnt seem to be very harsh, or at least not nearly as harsh as chlorine bleach. Remember, chlorine(in gas form) was used in WW1 as a weapon of mass destruction, by letting it loose on the battlefield when the wind was blowing in the right direction, and it would flow into enemy trenches and kill or injure thousands of people! Nasty stuff, and I'd prefer not to use it if possible!

    But is there a source for cheap/bulk generic Oxy Clean?

    BTW: The only real reason I used my backpack sprayer was because the extraction feature on the pressure washer wasnt working, but I think the backpack sprayer ended up being a better method of applying the bleach, because you can more precisely spray it exactly where you want it, whereas with the pressure washer, it comes out much faster and wider with the soap nozzle(black), and it ends up being wasted and it gets everywhere! But the backpack uses less, and doesnt get everywhere.
  7. Roof Cleaning Virginia

    Roof Cleaning Virginia LawnSite Member
    Messages: 189

    Chlorine has it's place, but usually not on decks or wood. Google "3 stepping" wood. You'll find that if stripping a prior sealer isn't required then the 3 steps are":

    Treat with sodium percarbonate (oxy bleach :)
    Power rinse
    Treat with a brightner/neutralizer

    Kudos to you for 'soft washing' houses rather than blasting every square inch with high pressure like the other guy did. Your process is much better AND much faster!
  8. georgialawn88

    georgialawn88 LawnSite Bronze Member
    Messages: 1,075

    back pack sprayer.... pick up tube through pressure washer..... my friend it can be so so much easier. please pm me. ill respond with my phone number. i can help you out if you really want to get it done faster

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