And another thing:  The way they soil and deteriorate is also different.


We've been studying the Municipal Auditorium Building in Kansas City,
which is clad in Indiana limestone.  As we (myself and Tracy Coffing)
were encircling the building with clipboards and cameras in hand, we
came upon an area that just looked different.  At first we tried
thinking this was weird limestone, but asked why was it so different.
The surface had random surface hairline cracks, and the overall surface
was blotchy with organic stains.  I could say more, the point is that
the deterioration and soiling pattern were visibly different from the
adjacent limestone.

It turned out that some years ago they enclosed a couple sections of
corridor along the west plaza, and clad it with cast stone.  So now we
hope there is remaining life in the swelling units to avoid replacing
them right away, but they will clearly deteriorate at an accelerated
pace and not last as long as the adjacent original limestone.  (Why they
didn't just use limestone, no one knows!)

Cleaning treatments have been tested, and they, too, affected the
different masonries differently.  The limestone comes cleaner and more
easily, mostly because it doesn't have those hairline cracks;  it's kind
of like a crazing, and there probably is a ferrous reinforcement within
the units causing the swelling.

Anyway, no time to get technical here, but I always find it interesting
to detect the difference between limestone and cast stone, and reactions
are always surprising when pointed out to people.  


QUINN EVANS | ARCHITECTS

Ilene R. Tyler, FAIA, FAPT

219 1/2 N. Main Street
Ann Arbor, MI  48104
[log in to unmask]
www.quinnevans.com
v 734.663.5888
f 734.663.5044

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