[TheForge] Update [OT - Asphalt shingle rot? (Lichen)]

[Bruce Freeman]

Well, this is amusing so I thought you might like an update.

Before dropping $60+ on copper flashing, I did some more Web-research.
 Turns out that those of you who spoke up are apparently right --
copper OR zinc cations will kill lichens.

So, what's the cheapest source of copper AND zinc metals?  You guessed
it -- "copper" pennies.  So now, if you look real close, you'll see
pennies scattered on the north-facing side of my roof, mostly near the
peak.  I had only about $5 worth of pennies around when I did this, so
might go buy another $10 worth for the effort.  I figure with rain and
winds, these will tend to wash down the roof, but I'll cross that
bridge when I come to it.

Meanwhile, I haven't given up on the notion of spraying the roof with
copper sulfate, but I've been trying to figure how and how much.
Seems to me that if a strip of copper foil across the roof will
protect the roof for 30 years or more (so claims that manufacturer),
then the concentration of copper needed could NOT be very high.  I
haven't actually worked out a number, but it must be vanishingly
small.

So I envision doing something like putting a half-teaspoon (if that
much) copper sulfate, dissolved in water, in a sprayer and spraying
the roof with it.  The problem with this is that I do NOT want to
inhale the stuff.  So I could use goggles and mask and wait till the
wind is right, or I could come up with an alternative way.  I could
possibly roll it on like paint, and if I did that I wouldn't even need
to cover the whole roof, as it will wash down from the peak to the
rest of the roof.

Still thinking on it.

-- 
Bruce
NJ