I have found that the problem is NOT usually the brick but the detailing,
the mortar and maintenance. Many 1920-30s buildings remain in good condition
even when not well maintained historically - the Chrysler Bldg being one.
These late 1950s bldgs were during technological transition from barrier
(solid) walls to early (partial) cavity wall construction. The idea of what
proper flashings, clear cavities, brick ties, drainage, and sometimes overly
rich portland mortar mixes were being worked out. This added with often lack
or misguided maintenance conspired to make these walls perform poorly. For
example, the Chrysler Building, 1930 barrier walls of white and black glazed
brick is generally performing well. The majority of the problems we have are
where repairs have been done - we also ran into poor brick as part of this
but these were from repairs later than 1960.

Generally, glazed bricks are like glazed terra cotta, historically built
into solid masonry moisture escapes through the mortar so the mortar must be
vapor permeable. The advantage that the glazed brick has is that there is
more mortar area. Later on terra cotta and brick walls started to be
detailed with cavities behind the face, 3/4" then as detailers got smarter,
larger cavities with weeps.

Eric Hammarberg
Director of Preservation
Associate
LZA Technology
641 Avenue of the Americas
New York, NY 10011-2014
Telephone: 917.661.8160 (Direct)
Mobile: 917.439.3537
Fax: 917.661.8161 (Direct)
email:  [log in to unmask]


-----Original Message-----
From: Met History [mailto:[log in to unmask]]
Sent: Thursday, December 19, 2002 9:18 AM
To: [log in to unmask]
Subject: 1950's glazed brick...how to detail?


From a recent news story about the 1959 blue brick building at 65th &
Madison, in New York City:

<<<The co-op's board of directors learned in February that decades of water
damage had left 40 to 65 percent of the blue bricks cracked and poised to
crumble on pedestrians. Unlike the porous red bricks, blue bricks are coated
with a thick glaze that traps water runoff. When that water freezes, it puts
pressure on the bricks, weakening their attachment to the underlying
concrete wall.>>>

Question to BP: Is there a way to detail glazed brick so that it does not
create moisture problems?  There's an astonishly early (1930) white glazed
brick building (as plain as anything form the 1950's) at 270 Broadway
(@Chambers) without any evidence of spalling or failure, even at the many
parapets.

Is the problem really with the brick - or with the surrounding matrix of
joints?  (Or was the brick, perhaps, abused by its parents, and thus is not
responsible for its actions?)

Christopher Gray

PS to Dan "Friend of  Travertine" Becker -- the Landmarks Commission voted
earlier this year to permit the coop to replace the blue glazed brick.   Not
a whimper.

Yr. Frnd.,  Lincoln Central




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