I like to think I've been around awhile; but to honest Im always
learning.Sometime ago there was a discussion about limestone; and for my own
curiousity I would like to tap back into it. For six months now limestone is
being pulled off the state capital as the I beams were suspect in rust and
the cause of many cracked stones.
.No such animal;to the Nth there was no lamination  of rust;
However most of the 1920 veneers were of 4"" veneer with 8" and some 12" on
the returns.
Clue #1...Indiana limestone after sample being sent; informs us that they
have plenty of stone in that sample but it is no longer quarried as it is no
longer "commercial" Clue #2 the building was sandblasted in the late 60's;
owning to its porosity.Clue #3  Most if not all the failed veneer is in the
4" stone.and the cracks are horizontal or with the bedding plane.... Sherlock
to Watson..After weighing;.Immerse the old 4" stone in water 6-8 hours and
repeating the same process with newly quarried stone...what say you?...Loyal
pinheads.
The shift in feeling here is the failure (cracking) is a recent
phenonomen(since 60's) and given the porosity of the stone;.... if you had
say two days of downpour ....followed by 3 days of hard freeze;.... 4" on
pourous  venneer isn't going to hold too well....on 400 ft of stone..
.without seeing it....any curve balls that  Watson and Sherlock need to
address?(besides PSI test).....Best Michael  ..