Lisa,

Yes, thanks for reminding me about the Conservancy's application on Ellis.
That is a good, quick and cost efficient method over worn out sheet metal,
even gutters with conspicuous holes.  I did another application, over 20
years ago, on a copper roof where every directly appliied elastomeric
failed (turned to jelly or silly-putty) because of chemical reaction to
prior patching compounds (black bitumin/asphaltic)  The solution was to
apply a barrier coat of fiberous neoprene before the elastomeric.  It
extended the life of the roof until replacement just recently...the
elastomeric was even colored green to look like aged copper.  I'm still
concerned with bridging any moving parts with membranes thin enough to
telegraph the historic roof pattern.  I suspect the application Ellen
refers to is a cost saving alternative to new metalwork without glopping up
and grossing the building out.

Thanks...Jim