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Author Topic: Where do black marks come from?  (Read 1735 times)

cuts_up

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Where do black marks come from?
« on: July 03, 2007, 12:45:06 PM »
I keep reading here and on another board about these black marks.  Where do they come from?  Are they on all types of surfaces?  I don't have them so I'm just wondering if it is something that I will eventually have, or if I'm just one of the lucky ones.
Kathy

Gary RV_Wizard

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Re: Where do black marks come from?
« Reply #1 on: July 03, 2007, 12:53:28 PM »
They are streaks of dirt left behind when dirty water runs down the sides of the coach and then evaporates. The dirt comes from the roof, which collects a lot from various sources (dirt/smoke in the air, tree sap and drippings, leaves & debris, road dirt (oils).

Black streaks are a major problem on rigs with porous rubber roofs, because the dirt builds up in the pores and then runs off every time it rains, dews or if a/c condensation pools on the roof. Metal roofs can have a similar problem with dirt in the seams, but fiberglass and hard-finish EDPM (e.g. Britek) does not generate much in the way of black streaks.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

cuts_up

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Re: Where do black marks come from?
« Reply #2 on: July 03, 2007, 01:37:06 PM »
Thanks.  We do have a rubber roof.  DH told me we don't have them because he washes the roof.  I just thought maybe there was more to it than that.


Kathy

KodiakRV

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Re: Where do black marks come from?
« Reply #3 on: July 03, 2007, 04:08:19 PM »
Thanks.  We do have a rubber roof.  DH told me we don't have them because he washes the roof.  I just thought maybe there was more to it than that.

I've heard from roof treatment folks that it works better to sweep your roof with a broom every couple of weeks than it does to hose it off.  Sweeping helps to get the dust and mildew spores off without getting them wet.  The mildew spores love to get wet.   ;D
Frank
Florida

Shayne

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Re: Where do black marks come from?
« Reply #4 on: July 03, 2007, 06:23:54 PM »
Hard to believe but some dummies actually vacuum their roof prior to washing.  I'm one of those guilty parties that have done that and probably will again when I wash the roof because of this AZ dust.  No big deal but sure gets a lot cleaner.  I think.   But there I go again  Thinking.
Old, Stubborn, Opinionated, Set in my Ways, and Independent,  IMHO

Gary RV_Wizard

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Re: Where do black marks come from?
« Reply #5 on: July 04, 2007, 07:18:13 PM »
Quote
DH told me we don't have them because he washes the roof.

Keeping the roof clean certainly helps, as long as you clean it often enough. And "often enough" is dictated by the dirt/crud in the air or overhead in trees. Even the number and size of birds flying over...  ::)
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL