Stop mildew/algae build-up on old vinyl siding?

Stop mildew/algae build-up on old vinyl siding?

Rental Property Investor · Charlotte NC Fort Mill SC Lake Wylie SC, SC · Member since 2009 · 174 posts · 103 votes

I need to figure out how to stop this mildew or algae stuff that shows up on one of my rental house's older vinyl siding.

I end up having to pressure-wash this crud off at least yearly, but it really needs it 2-3 times per year! It's really ugly. What can I do to prevent it from coming back all the time?

The siding is otherwise in excellent condition.

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OR · Member since 2008 · 1k+ posts · 845 votes
16y

Zinc on the roof.

You can buy Moss B Gone and sprinkle on the roof. You can buy special zinc strips to put on the roof, or you can place galvenized chicken wire along the ridgeline.

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  • OR · Member since 2008 · 1k+ posts · 845 votes
    16y

    Zinc on the roof.

    You can buy Moss B Gone and sprinkle on the roof. You can buy special zinc strips to put on the roof, or you can place galvenized chicken wire along the ridgeline.

  • Rental Property Investor · Charlotte NC Fort Mill SC Lake Wylie SC, SC · Member since 2009 · 174 posts · 103 votes
    16y
    Originally posted by P NW:
    Zinc on the roof.

    You can buy Moss B Gone and sprinkle on the roof. You can buy special zinc strips to put on the roof, or you can place galvenized chicken wire along the ridgeline.


    Put this stuff on the roof to stop the mildew/algae that forms on my siding? huh?
  • Member since 2009 · 499 posts · 117 votes
    16y

    This is probably on north side of the house. I never had that prob but if I did I would try that mold preventer that Menard's sells for interior use. OR look in same place for a similar outdoor product.

    Is this well shaded? Any possible way to increase sunlight by trimming trees,bushes etc?

  • Real Estate Investor · St. Louis, MO · Member since 2010 · 153 posts · 104 votes
    16y

    I have this same problem on my personal home. There is a product called JOMAX, you can find it at Home Depot or Lowes.Mix per instructions w/ bleach water in a pump sprayer and just soak the affected area. Then take your hose with a good sprayer attached and hose the mildew right off. If you've got it bad you may have to repeat or let it soak a bit . but do not let it dry on the siding, or you,ll just have to start over. I use this every other year as the mildew shows up. If I just clean it off, the mildew comes back that same summer /fall so the JOMAX will inhibit growth for a time.
    Be sure to spray off any desirable plants w/water before and after using this.
    Good Luck
    Chris

  • Rental Property Investor · Charlotte NC Fort Mill SC Lake Wylie SC, SC · Member since 2009 · 174 posts · 103 votes
    16y
    Originally posted by Just Don:
    This is probably on north side of the house. I never had that prob but if I did I would try that mold preventer that Menard's sells for interior use. OR look in same place for a similar outdoor product.

    Is this well shaded? Any possible way to increase sunlight by trimming trees,bushes etc?


    It's on the NW side of the house, and it's actually the one side of the house that has no trees or bushes nearby. That area gets the most sun, really. I don't know. I think it's just old siding that's lost its top coat (if there is such a think), and now everything just clings to it. I was stabbing in the dark, hoping something like Rain-X or something might be a good option. I'll try some of these suggestions. Hey, at least it's cheaper to have it pressure-washed every year, rather than replace the siding, right? :D
  • Loveland, CO · Member since 2008 · 1k+ posts · 123 votes
    16y

    I'm not sure how humid it is in your part of the state, but I've seen lots of houses in Houston with this problem. SOMETIMES the problem is caused by the idiot who decided to put vinyl on OVER THE TOP of the old, maybe faux board siding.

    If there was moisture in the old siding it's going to manifest itself by creating condensation on the outside. I've seen houses where the original siding was just crumbling from years of retaining moisture.

    Is there a way you can easily pull some of the siding off and see what's going on underneath?

    Cleaning it is just treating the symptoms, not the cause. You need to find out the cause.

    Frank

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