Architect's Guide to Complex Façades

Katy Devlin
March 30, 2015
COMMERCIAL, RETAIL, FABRICATION : ARCHITECT'S GUIDE

Key to Complexity

James Carpenter's Iconic, Yet Simple, Designs

Case Studies

Key to Complexity

The last decade has witnessed a proliferation of increasingly sophisticated building modeling and design tools that have helped to herald in a new era of architecture, one in which creativity seems to feel no bounds. This new era of possibility has greatly affected façades, as designers create building envelopes of ever-growing complexity.

“Demand for high-performance curtain walls and improved design programs have led to an increase in complex curtain walls with unique geometric shapes, large spans of glass and three-dimensional planes,” says Jeff Razwick, president, Technical Glass Products. “Many of these applications go beyond the curved and segmented curtain walls that gained traction over the course of the last few years. We’re seeing more interest in curtain walls with multi-faceted glass panes, folds and inverted planes.”

“The dominant trends are twofold,” adds Mic Patterson, vice president of strategic development for Enclos. “The first is the escalation of geometric complexity in the building skin, enabled by the widespread adoption of sophisticated yet accessible design tools. … The second is the expanding palette of materials and processes being applied to façade design. It used to be all aluminum and glass, with some occasional stone or composite panels. Now we are seeing [glass fiber reinforced concrete], [fiberglass reinforced plastic], castings of various sizes, fabrics, metal meshes, and lots of [architecturally exposed structural steel].”

However, the move away from traditional façades presents new and different challenges for the entire building team throughout the design and build processes. Complex designs require careful considerations of cost, discussions of materials and material processes, consistent communication throughout the building team, and more extensive use of modeling tools and physical mockups.

This Architects’ Guide to Complex Facades, the sixth installment of Glass Magazine’s Glass & Metals series, examines these critical considerations and notable challenges associated with the design and execution of complex façades.

Beyond design-bid-build

“There is a better way than design-bidbuild,” said Lawrence Scarpa, principal at Brooks+Scarpa, during the recent Facades+ conference in Los Angeles. Complex projects can’t be effectively executed with the more traditional design-bid-build process, said Scarpa and other building and design officials during the event.

In the standard design-bid-build project delivery process, an architect develops the design before sending it out to bid. The various trades first see the scope of the project contract during this stage, thus there is very little room for communication and collaboration between the trades and the design team, sources say.

Complex projects, however, require close collaboration among the architect, the trades and the suppliers to develop a system that can be successfully implemented. This delivery process, called design-assist or design-build, brings the project team together in the early stages of a project.

“Innovative projects need to be treated differently than business as usual if you want to manage the risk that accompanies innovative project content,” Patterson says. “Design-assist develops as a strategy in response, with a clear goal of engaging relevant suppliers, consultants, and contractors very early in the design process.”

During the early stages of a designassist project, consultants, subcontractors and suppliers work with the design team to develop solutions to achieve the architect’s vision. As such, the designassist or design-build processes help to create partners on projects, sources say.

“While involving the supplier earlier with the design team is beneficial for any curtain wall project, it’s even more valuable when working with complex curtain walls,” Razwick says. “The more complete the supplier’s understanding is of how an architect envisions the curtain wall playing into the building, the better our ability to customize the system, help refine drawings and set realistic expectations. This can also help ensure the project team is aware of any extra time required for testing or product development, and helps keep the project within budget as the curtain wall is refined to meet project needs.”

Early involvement and collaboration is critical on complex façade projects, as the envelope team is often asked to combine elements and materials that “don’t usually work together,” says Aaron Margalit, project manager for W&W Glass. “How a façade works for an architect aesthetically may mean combining systems that are not designed to work together. This means bringing in the various vendors and contractors ahead of time to create a customized and adapted system—to create physical marriages between the systems,” he says.

This process does require additional education, particularly when a team is collaborating for the first time. The team may need to be trained in things such as installation methods or in using and reading modeling tools. “There is an educational process with a design-assist contract,” said Paul Martin, director of engineering sales for complex façade engineer and fabricator Zahner, during the Los Angeles Facades+ conference.

“If a project delivery team hasn’t worked with a particular glazier or subcontractor before, it’s also critical to factor in time for hands-on training and collaboration,” Razwick adds. “The installation of complex curtain walls can differ from more standard applications, requiring technical support and onsite custom work, particularly if new materials or shapes are involved. Collaboration between the trades can help ensure these complexities are understood, and that the curtain wall is installed correctly on-time and within budget—all of which ultimately affect the quality of the job.”

Rationalizing the Geomoetry

Translating a model design into something buildable. In such a process, "there is often a consolidation of part types such that every component of the design is not unique," says Mic Patterson, director of strategic development for Enclos. "This process can be far more challenging and time consuming than the generation of the original form."

Modeling and mockups

Computer modeling makes complex facades possible. However, just because a design can be modeled doesn’t mean it can be built. It’s in the early stages of a project where collaboration between the architect and the manufacturer is critical, as the team works to develop real-world solutions to match the modeled vision.

Complex façade designs “often present challenges down the line to the facade contractor and fabricators tasked to competitively implement the design,” Patterson says. “With tools like Rhino, it is quite easy and quick to generate a compelling form of incredible geometric complexity—a visit to a studio critique at any architecture school will validate that. Practicing with these tools has produced some stunning architectural form, but the process of realizing that form involves complexity of a higher order of magnitude.”

Contractors and material fabricators can assist the design team in translating the models into something that is not only buildable, but also cost effective. This process is “often referred to as rationalizing the geometry,” Patterson says. “This process can be far more challenging and time consuming than the generation of the original form.”

“In addition, while BIM systems and modelling software have come a long way in the last decade, it’s still important to ensure the selected materials and systems can achieve the look and functionality the architect is after,” Razwick says. “Collaborating with the supplier or manufacturer can help provide quick, correct answers for the architect or general contractor. Suppliers may offer various support tools such as shop drawings, additional installation information, and research and engineering support, as well as supporting more realistic budgeting early in the design process. Not getting an early handle on a realistic design for meeting budget, potentially wastes the various project players’ time and impacts the project schedule too far down the project delivery timeline.”

Because of the custom, untested nature of complex facades, physical mockups are also an important part of the process. Architects may build both small-scale mockups to check the visual appearance of the built structure and full-size mockups for performance tests. Challenging installation procedures may also be verified using a physical mockup, sources say.

“There is no substitute for mockups,” Martin said during Facades+. “Factors like color are things you can’t measure or visualize in a model.”

Process challenges

Even with the emergence of new tools and technologies for creating complex designs, project teams are faced by notable challenges at all stages, from meeting budgets to managing expectations.

One major challenge is openbid requirements. Contractors and suppliers brought on to assist during the design phase are often not guaranteed to win the project once it goes to bid. This is particularly challenging on public jobs with mandated bid processes, sources say.

However, an architect can work to communicate the quality control and eventual cost saving benefits to working with a preferred subcontractor or supplier. “There is a huge misconception that the price is higher if you go with just one company,” said James Carpenter, principal for James Carpenter Design Associations Inc., during Facades+. “I advocate to my clients that they will get a better product [if they work with our preferred manufacturer or contractor]. If there is a fixed budget, we can work with that company to try to come up with a cheaper solution that carries the same aesthetic idea.”

Another challenge is a lack of budgeting for the design assist portion of the job. Architects and building owners must budget for the additional design support provided by contractors, subcontractors or material suppliers during the early stages of a designassist project. However, this additional cost element is often not considered, sources say.

“There are many, if not most, in the industry that think design-assist is about getting input from a contractor early on for free,” Patterson says. “This is not it. And unfortunately, it’s not even enough to bring in the appropriate expertise as a contracted part of the design team, although that is certainly a great improvement.”

This part of the design-assist process is evolving, as more and more projects require this type of project delivery. However, much more work is required to establish reliable methods of an equitable and effective design-assist process for all project team members, sources say.

Working with custom, complex designs demands additional flexibility. Developing a system for the first time may require additional time and may stretch budgets. Making allowances for the potential of time and monetary costs at the start can ease these pressures, sources say.

“One common problem project teams face when working on complex curtain walls is establishing realistic expectations,” Razwick says. “For instance, it might be necessary for the subcontractor or glazier to start field work earlier to account for onsite custom work. If this time isn’t built into the project scope, it can lead to project delays that cost more in the long term.”

Three Questions for a Complex Façade

From Aaron Margalit, project manager for W&W Glass

Can it physically be done?

“We first do a structural analysis of the project. We work with the architect to understand the geometry, and we say ‘this is what we can do for you.’ Sometimes their computer software isn’t the same as ours, so this may require converting models into shapes that we can analyze. Once we determine what can physically be done to create the desired design, we sit down with the architect to make it happen.”

Can it be done withing the budget?

“Once we determine whether the architect’s vision is physically possible, we move onto the budget. Can it be completed at the cost, within the schedule? Do we have to change materials to save on cost?”

Can it be installed?

At the installation stage, “we work with the [subcontractors] to make sure they are all using the computer models the same way we are. Some subs may be building off paper, so we might have to supply the models to the other subs on the job so they can integrate properly. And, we have to have a clear understanding of the [work of the] other subs on the job. … We build the model and do a scan of the building in 3D to see if there is any overlapping, so all the crashes can get resolved. … And once onsite, we make sure the work is done correctly—we are checking all the subs’ work to make sure the sheet rock, stud walls, etc., are keeping [to the] tolerances.”

Key to complexity

As architects continue to push the envelope of design, complex curtain walls will become more ubiquitous, and thus increasingly collaborative design and build processes will become more critical. Early involvement of players throughout the façade team can ensure problems are addressed in the design stage, and can assist architects in meeting budget. “When you are developing massively complex, difficult, always custom systems, you have to push the design up front. … You have to work with the design team,” Martin says.

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Katy Devlin is editor for Glass Magazine. E-mail Katy at kdevlin@glass.org.