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™ for further updates from the conference.

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