Power wash vinyl siding

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Old 12-03-15, 12:43 PM
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Power wash vinyl siding

The north side of our summer house gets a green mildew coat every year. I have always scrubbed it from a ladder in the past. I've decided I'm too old for that anymore and I want to hire somebody to clean it. Is there a problem with pressure washing the vinyl siding?
 
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Old 12-03-15, 12:54 PM
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Problem? Not likely, but not all installers put a wrb behind the siding. If you have existing siding behind the vinyl siding, it should be fine. If you have a wrb behind the siding, it should be fine. If someone installed new windows in an unapproved manner (not incorporating them into the WRB properly) there is a chance you could get some leakage at the tops of windows. So that is one area you might be careful.

Generally, if you spray downward rather than upward... and if you spray away from j-channels rather than directly into them, you will be fine. Vinyl siding isn't waterproof in the first place... it's just a cladding.
 
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Old 12-03-15, 12:58 PM
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No! I do it every year. Be careful and try not to spay under the siding to lift it up. Spraying down or sideways is the best method. I use a typical store bought solution meant for home siding. Stubborn stains may still require some scrubbing. And I learned not to be too fussy. From a distance the house looks clean. If you have wood or brick be careful not to use a high intense stream. It will etch the siding. Vinyl seem to be OK to use the highest setting. At least I never had any bad results or etching of the siding.
 
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Old 12-03-15, 02:51 PM
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Instead of scrubbing it from a ladder why not mix up bleach [or house wash] in a pump up sprayer, spray the siding from your ladder, let it set but not dry and then rinse with your garden hose .... if you want to save the diy $
 
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Old 12-03-15, 02:56 PM
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I've had good luck with marksr's method except I use Clorox outdoor bleach. I mix it up in a pump-up garden sprayer and apply it to the wall when the wall is dry. Much of the dirt, mildew and algae will be gone before you even hit it with the hose. It also seems to help with the reoccurrence of mold though I don't know if it does any better than mixing up your own bleach solution.
 
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Old 12-03-15, 05:04 PM
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I've tried spraying with several cleaners, including diluted bleach, with little luck. It gets the dirt, but the green stuff takes some serious scrubbing. I started years ago using scrub brushes, then sponges, then greenie pads. They all required more elbow grease than I have left in my elbows. Magic Eraser works very well but it still takes scrubbing. The house is two story plus gable height and a garden sprayer won't reach.

Not trying to be negative but it looks like a power washer is in my future.
 
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Old 12-03-15, 05:15 PM
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The north side will always grow moss and mold. If it's bad enough you may find yourself doing twice every summer. I usually wait for those really hot days when the water spray and getting wet feels good. I also have a two story house. I use a step ladder. On those high places you can't avoid spraying up under the clapboards, but the force is diminished enough so that no real harm is done.
 
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Old 12-03-15, 06:04 PM
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Doubt a power washer will remove 100% either. Mildew is a mold and mold will stain vinyl. The longer it's been on there, the worse it will be and it can eventually be stained permanently. Zud is a good one to try if you need to scrub. Soft Scrub w/bleach is another.
 
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Old 12-03-15, 07:13 PM
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My previous house had vinyl siding. I found that a pressure washer by itself did little. I would take a five-gallon bucket and add a couple of gallons of water, then some Simple Green, maybe a four-to-one dilution, and use a long-handled car wash (soft) brush to thoroughly wash the wet siding and then use the pressure washer to rinse it off. I'd do a panel about six to eight feet wide and from top to bottom at a time. (It was a single-story house.)

I used the Simple Green because I didn't want to kill the grass as I suspected any harsher detergent would do. I only did this every second or third year but once a year probably would have been better as the house was really dirty waiting that long between washings.

I know that the north side of that house did have a tendency to get a bit green but I never had any problem getting the green to come off as long as I used the brush and detergent.
 
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Old 12-04-15, 04:28 AM
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I used to live in fla where mildew is king I'd wash my house every year and if I wanted to keep it nice looking - the north side got washed every 6 months. Pressure washers can be a nice aid when cleaning a house BUT if care isn't used you can cause damage! As mentioned already care must be used to keep from forcing water behind the siding. Also around windows and doors. I've seen damage to drywall where the windows weren't perfectly sealed, the same can happen at the soffit.
 
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Old 12-04-15, 06:17 AM
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I think you have made the problem worse with some of your aggressive cleaning. Especially using the green pads. You may have created micro scratches in the siding which allow algae and mildew to get a firm grip and possible even get into the microscopic pores of the vinyl. Most vinyls have a smooth skin, even with the texture, that doesn't allow mildew and dirt to get "into" the vinyl. When that skin is broken with age or agressive scrubbing it's more prone to getting dirty and is much harder and sometimes impossible to clean.
 
 

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