City Hall contractors play match-maker

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Milwaukee City Hall Project Manager Terry Watson, of J.P. Cullen & Sons Inc., showcases one of the on-site mockups contractors are using to ensure the new bricks and sculptures match the originals on the building.

Daily Reporter Photo/Sean Ryan

From afar, Milwaukee’s City Hall looks all squared away, but, like a person’s
face, its imperfections become more obvious the closer one looks.

From across the street, the 1896 building’s brick walls look uniform in
color, but up close, the bricks reveal a spectrum of ruddy colors ranging from
muddy to khaki. That range of colors can never be perfectly recreated. The stone
they were made from a century ago is gone now, and modern bricks are fired mostly
by natural gas, not the coal or wood that fired City Hall’s bricks and
stained them with smoke.

The mortar joints separating the bricks range in width by fractions of an inch
but, multiplied by hundreds of rows of bricks, the sixths of an inch add
up. Before the project started, engineers scanned the entire building exterior
with a laser and have mapped every grain. They found that one side of the clock
tower had 80 rows of bricks, but the opposite face had 82.

So the challenge for the project’s architects and contractors becomes
how to perfectly recreate some of these imperfections and correct others without
changing the building’s appearance. In October, members of Milwaukee’s
Historic Preservation Commission publicly voiced their concerns about some of
these issues to the Public Works Committee.

“We’re all looking to achieve the end result, and that is a product
that will stand the test of time and be true to the historic architecture of
the building,” said Historic Preservation Commissioner Patricia Balon.

“It’s not a confrontational issue.”

Wider joints, too

Members of the commission are keeping a close eye on the project and are working
with city staff and general contractor J.P. Cullen & Sons Inc. to find solutions,
or at least the closest thing to them, for the more difficult challenges. As
an example, the project’s original brick fabricator gave up on the challenge
of matching City Hall’s shades. The new fabricator, Canada’s Brick
I-XL, is trying to make the 150,000 new bricks match the center of the original
bricks’ color spectrum, but, of course, its bricks will also have a range
of shades, said Milwaukee Facilities Manager Gary Kulwicki.

The contractors are creating mockups of the brick walls and building sculptures
on site that demonstrate how the new walls will look and how they’ll match
up with the replacement sculptures that are being fabricated in California.

A look at the brick mockup caused concern among commissioners that the new
exterior walls would have wider mortar joints than the originals. Contractors
100 years ago built walls with more narrow joints, since mortar lets in more
water than stone, said Kulwicki. Modern contractors build their joints three
times wider than the narrowest joints on City Hall, he said.

The brick-laying contractor, Arteaga Construction Inc., has agreed to stick
to the widths contractors used 100 years ago.

“We have come to the consensus that we want the tightest joints possible,”
Kulwicki said. “They (the contractors) don’t have any problems with
doing that.”

“What they’re shooting for is what’s up there,” said Terry
Watson, project manager with J.P. Cullen. “We lasered the building, so
we know exactly what all the dimensions are.”

The Historic Preservation Commission, after looking at mockups that included
the terra cotta sculptures that will replace City Hall’s originals, raised
concerns about their size. California’s Gladding, McBean & Co. is fabricating
13,000 new sculptures using the same methods that created the originals; 2,600
are done already.

The company is creating molds of the original sculptures. Its artisans pack
the terra cotta into them by wadding the clay up and pitching it into mold like
a baseball, Watson said. Then, artists hand-comb ridges into them before they
are fired in a kiln. They take three to six weeks to dry.

The tricky part is terra cotta sculptures shrink about 8 percent to 10 percent
in a kiln, making it more difficult to make a clone of the exact same size.
Some of the sculptures have been the wrong size, or were combed too much and
too small. Those just get thrown out, Watson said, and reported to Gladding,
McBean’s quality-control people in Chicago, and the process moves forward.

Just last week, the Historic Preservation Commission, city and contractor all
signed off on the mockup of the dormers, or brick and sculpture structures that
surround City Hall’s windows, after seeing it put in place on City Hall’s
exterior wall. Cullen plans to have all 20 dormers installed by April, Watson
said.

Next, they’ll do the same using mockups of the clock tower, gutter lines
and other fine points.

“You really don’t know whether you’ve got it 100 percent correct
until you actually have it on the building,” Kulwicki said. “We all
agreed to it and can say now that (Cullen) can proceed with the rest of the
dormers, and we’re doing that process over and over again on different
parts of the building.”