Expert Reviews Curtainwall Design Challenges,
Problems and Solutions

April 13, 2010

"Curtainwalls
are essentially an exciting subject," began Karol Kazmierczak,
senior building science architect with Morrison Hershfield Corp.
in Miami, "but only with construction professionals familiar
with them."

Kazmierczak spoke to an audience of architects, primarily, yesterday
during the Building Enclosure Science & Technology (Best 2)
conference, taking place this week in Portland, Ore., which is presented
by the Building Enclosure Technology and Environmental Council in
collaboration with the Building Enclosure Council. His presentation
reviewed fundamental classification and challenges associated with
the design and construction of curtainwall and provided a "balanced,
holistic approach" to their construction.

"Curtainwalls have been around for over a century; however,
they still present a challenge for building designers, curtainwall
manufacturers, and installers," Kazmierczak explained. "Typical
sources of confusion are structural tectonics, façade control
functions and division of responsibility."

One of the challenges posed by curtainwalls, he explained, is that
the fact that there is no "rigid" classification system,
given the fact that they come in a variety of materials and forms.
However, he pointed out that the name "curtainwall" has
become associated "with a light, secondary rigid framing system
filled or covered with a lightweight cladding." This group
can be classified by a number of characteristics. This could include
classification by place of assembly (stick systems, unitized, etc.);
by function (fire-rated, acoustic, blast-resistant, etc.); by mullion
materials (wood, steel, aluminum, composite, glass, etc.); by mullion
type (tubular, truss, cable, structural glass, etc.); by glass type
(reflective, low-iron, anti-reflective, etc.); as well as several
others.

He also discussed three primary challenges of curtainwall: joinery,
scope of responsibility and façade functions.

"Curtainwalls are famous for complicated joinery, movement
from the exterior and movement from the curtainwall itself,"
he said, explaining that in the past joinery transferred the entire
load to the building so there was not much differential movement.

"Now, the livelihood of deflection [is] accommodating of the
building movement," he said. He added, "Architects tend
to stretch the structural span as far as possible."

During the design phase there can also be confusion over scope of
responsibility. Kazmierczak said there are often gaps in communication
and misunderstood delegation of responsibilities on these projects.

The third area of confusion involves the façade function.

"Facades have never before been so complex. There primary function
is to be shelter for the occupants; this has become somewhat forgotten,"
he said, explaining that sometimes the architectural community is
more focused on the aesthetics than the function. He explained that
the façade functions need to be considered in conjunction
with each other because they overlap.

Kazmierczak also briefly talked about warranties, and said they
are not always the best indicator of quality or durability.

"Warranties should not be the only way you assess the goodness
of the material," he said, adding that testing is also critical.

Stay tuned to USGNN.com™ for further updates from the conference.

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