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Anybody Know what these brown "line" stains are on my vinyl siding???

Anybody Know what these brown "line" stains are on my vinyl siding???

Old 03-17-13, 01:25 PM
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Anybody Know what these brown "line" stains are on my vinyl siding???

HI Guys!

Looking for some help. These weird streaks appeared last year, and now they are getting a bit more pronounced (please look at pic). I have no idea what it is,it doesnt seem to look like the artillery fungus issues i've seen, and its way high up so I cant see if it washes off or not or tell the texture (i.e. sticky, whatever). First, the facts:

City: Toronto
Location of issue: Only the north side of the house - No other siding is displaying the problem. House backs and sides onto ravine (north side of the house that sides on the ravine is displaying the problem).

Now the detail, although it looks like dripping, I believe it is actually crawling "upwards", perhaps from the siding drain holes (?). This starting last year and initially I thought it was a burn mark from some kids maybe firing a firecracker at the house but then noticed the weird pattern. I can't check for moisture issues on the inside of the house, because the other side of the wall is our great room that has no attic, but displays no signs of moisture inside the house. Soffit looks clear, it looks like the underside of siding is getting darker quicker as well. Its about 30 feet up on an angled ground so its pretty treacherous trying to get up there with a ladder by myself......but i may have to!!!

Has anybody seen this before and know what is causing it?? I guess I have to pay a pro to replace or clean it because its real hard to get to but I'd sure love to know if there is anything I can do my self to fix this and spare the expense. Particularly if there is any concern from a health persepctive (i.e. mold). House was built in 1996, no other issues, great builder. Bug infestation between the tyvek and the siding????

Help! Thanks to all.
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Old 03-17-13, 02:10 PM
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Old 03-17-13, 03:08 PM
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I'd be suspicious of a possible leak that is coming from the roof and releasing through the soffit. If you look, every course of siding has black stuff on the bottom of it. In that one area it is migrating downward as it drips from one portion of lap siding to the next. As Tow_Guy mentioned, I think it is mildew or fungus of some sort. I would wait for the next big rain storm, grab an umbrella and head out to view what is happening during a rain event. You might be surprised at what you find, but I suspect that there is a water drip in that area.
Old 03-18-13, 09:05 PM
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Could be a little dip in the siding from when it was installed. There are usually condensation drip holes on the bottom of the siding lip. That area stays a bit moister than other spots and it shows. A good power wash and it will be gone for a year if you are lucky. If you really want to check it out. The siding can be pulled to check behind it. I don't think you will find anything there.
Old 03-19-13, 04:50 AM
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A big mistake many diyers make when PWing vinyl siding is trying to do it all while standing on the ground. It's best to do the majority of PWing at a downward angle. Spraying upward forces water behind the siding. If the siding was installed properly, it can handle a little water behind the siding but it's best to limit the amount of water the best you can.

I agree with the others that you should inspect it during a rain storm - that will give you a better idea as to what is going on

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