Hello everyone.....
Donna,
Donald Baerman AIA presented a paper on this about 8 or 9 years ago.  He had
done some chemical analysis and found that the acidity of rain water after
running down cedar shakes was 20 times the acidity of the actual rain.  Now
that's all I can remember, so I put a call into him to see if he could post
us something.  I'll let you know.
    As for LEAD coated anything.  If you read the latest EPA regulations,
and believe their concerns, then do not specify or use it.  Low enforcement
levels do not mean it is safe or legal for us as craftsperson's or designers
to contribute to lead contamination when there are other products available.
If dust, paint chips or fumes from leaded gas can contaminate soil beyond
the Permissible Exposure Levels then I bet rain run off from lead coated
copings can too. (There's a thesis and while your at it check your child's
"lead" refills.  Are they graphite?  How about the .06% of lead allowed in
latex paints?)  If there is a health risk for artisans leading windows then
there must be a risk to roofers working with lead.  Its too bad another
great material will bight the dust.  Beware... and watch for lots of
litigation this year.
Best,
Leland

Leland R. S. Torrence
Conservation, Restoration and Management
17 Vernon Court
Woodbridge, CT  06525
Phone:  203-397-8505
Fax:  203-389-7516
Pager:  860-340-2174

----- Original Message -----
From: "Cubberly, Donna R (Donna)" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, April 30, 2001 1:38 PM
Subject: Re: Cedar and Copper


> John:  Thanks for your reply.
>
> It is difficult to believe that there is no documentation on this subject
> since it seems that it would be easy enough to prove or disprove by
> performing chemical analyses.  As a matter of fact, I have a friend who is
> about to begin a master's degree program in chemistry and I have begun
> urging her to undertake the task.
>
> Thanks again.
> Donna
>
> > ----------
> > From:         John Callan[SMTP:[log in to unmask]]
> > Reply To:     [log in to unmask]
> > Sent:         Monday, April 30, 2001 1:03 PM
> > To:   [log in to unmask]
> > Subject:      Re: Cedar and Copper
> >
> > Donna:
> >
> > When you find it, please let me know too.  There is plenty of oral
history
> > among preservationists to indicate that cedar upstream from copper, as
in
> > gutters is bad and that pin holes develop in the gutter...and I have
seen
> > this
> > and have photographs.  I have seen copper stay shiny and not build up
the
> > patina downstream from cedar...and I again I have the photographs.  But,
I
> > have
> > found no learned publication on the subject...and I would very much like
> > too.
> > I also have been using copper ridge flashings on cedar roofs with a half
> > inch
> > or so exposed because oral history holds that the run off will kill mold
> > and
> > moss and such.  Seems to work, I don't think I've documented it.
> >
> > There's a couple of outfits selling chemical treatments to speed up the
> > patina.  And there is a contractor in Harrisburg PA who puts lacquier or
> > something on copper to prevent it from developing a patina.
> >
> > Hope this helps more than it confuses.
> >
> > -jc
> >
> >
> >
> > "Cubberly, Donna R (Donna)" wrote:
> >
> > > Can someone direct me to documentation regarding a chemical reaction
> > between
> > > cedar and copper, particularly with regard to cedar
> > facilitating/expediting
> > > the development of the light green patina on copper?
> > >
> > > Thank you.
> > > Donna R. Cubberly
> >
>