Skin Metrics

The Wicked Problem of Façade System Assessment


  • Keith Boswell Skidmore, Owings & Merrill
  • Stéphane Hoffman Morrison Hershfield
  • Stephen Selkowitz Lawrence Berkeley National Laboratory
  • Mic Patterson Facade Tectonics Institute



Façades, building skin, curtainwall, building envelope, façade performance metrics, façade performance , sustainable façade systems, building resilience


Building façades are key to the building systems integration necessary to realise critical health, carbon,
resilience, and sustainability goals in buildings and urban habitats. In addition, façade system design
and delivery may be the most rapidly developing building technology, with novel materials, assemblies
and techniques introduced in the marketplace frequently. However, these developments are occurring
in the long-running absence of an appropriate framework for façade system performance evaluation.
There has been no general convergence on the assessment criteria nor, for the most part, on the metrics
to accompany those criteria. The convergence of myriad and often competing variables that characterise
the building façade mark the development of a comprehensive integrative assessment framework as
a wicked problem, The lack of such a framework inhibits meaningful development and adoption of
innovative façade technology, leaving aesthetic considerations to drive application and compromising
the evolution of performative system behaviour. It prohibits a meaningful comparison between façade
systems, or of new techniques with prior applications. Adoption of new façade technology is constrained
as designers, building owners, and, most importantly, authorities with jurisdiction at the level of city
government are unable to accurately value its performative contribution to occupants, to a building
project, or to the urban environment.
Very early efforts and thinking in the development of a comprehensive Integrative Façade Assessment
Framework by the Façade Metrics Working Group of the Façade Tectonics Institute are documented
here. A preliminary review of existing façade system metrics and assessment strategies reveals they
are fragmented, too narrowly focused, and lack the comprehensive integration to provide an accurate
evaluation. With a strong focus on energy performance in new buildings, deep and vital considerations
like retrofit and renovation strategies, passive survivability, durability and service life, and resilience are
often neglected entirely. We outline some new directions that begin to address these gaps and suggest
a data-rich, visual framework and knowledge-sharing platform to advance progress with enhanced
metrics and façade systems evaluation and comparison.

Author Biographies

Keith Boswell, Skidmore, Owings & Merrill

Keith Boswell's design approach is to design, develop, and integrate, detail and system concepts in the early project phases and continue refinement through construction documents and the construction phase.

As the Technical Partner for SOM’s San Francisco office, Boswell orchestrates and oversees detailed design and construction documentation for all San Francisco projects. Since joining SOM in 1981, he has worked on high-rise office buildings, museums, retail spaces, government projects, amusement parks, residential and mixed-use complexes, and international and domestic airport passenger terminals. He has also developed expertise in overseas projects, working with local owners and contractors to use regional materials to meet international standards for quality and performance.

Boswell is a specialist in designing and executing technically complex building systems, such as curtain walls, elevator systems, and special construction. He is actively engaged in the research and application of materials and systems for use in SOM designs.

Among his accomplishments overseas are the Beijing headquarters for Lenovo (China’s largest computer company), Poly Corporation Headquarters in Beijing, Poly Real Estate Headquarters in Guangzhou, and Ayala Tower One and Philippine Stock Exchange (both in Manila).

Stéphane Hoffman, Morrison Hershfield

With a Master’s degree level education that combines structural engineering, building science and architecture, Stéphane brings a well-balanced consulting approach to the building envelope; blending scientific analysis with an understanding of aesthetics considerations. He is particularly adept at providing innovative design concepts and construction alternatives that provide value by improving durability and increasing energy efficiency. As a key technical leader at Morrison Hershfield, Stéphane has worked on projects throughout North America. He led the expansion of Morrison Hershfield’s building science business across the United States and pioneered their Facade Engineering practice focusing on conceptual design of cladding and glazing systems. He now leads their Building Science Analytics Group combining Facade Engineering, Energy Modeling and Envelope Component Modeling to assist teams design high performance buildings. Stéphane holds a Masters of Engineering from McGill University and a Master of Architecture from the Université de Montréal. He is a licensed professional engineer.



Stephen Selkowitz, Lawrence Berkeley National Laboratory

Stephen Selkowitz has spent 40 years developing and promoting sustainable building technologies and design practices and working to drive those innovations into widespread practice. As Senior Advisor for Building Science, Lawrence Berkeley National Laboratory, he now serves in a part time research and strategic planning role at LBNL after leading their building performance teams in R&D and deployment of energy efficient technologies and sustainable design practices. He complements his ongoing LBNL research role with a new advisory and consulting role in supporting the building industry’s transition to more sustainable practices. He is an internationally recognized expert on high performance buildings, ranging from policies to promote Zero Net Energy building solutions and activities to develop design tools and processes that guarantee delivery of workable solutions, to a technical focus on window technologies, facade systems, shading solutions, daylighting, and integrated building systems solutions. He led the LBNL Windows and Daylighting Group for 40 years and the LBNL Building Technologies Department for 25 years, partnering with industry to develop and demonstrate new technologies, systems, processes and tools that address not only energy and sustainability but enhance human comfort and performance. His research group collaborated with numerous building owners and design teams to advance cutting edge, but pragmatic solutions, most recently through the use of full-scale performance testbeds and mockups, both on-site (New York Times Headquarters) and at LBNL (FLEXLAB). He serves as Scientific Advisor to several international building science programs that address zero net energy building solutions, serves as a consultant to industry, has spoken at over 400 scientific, business and industry venues and authored over 170 publications, 5 books and holds 2 patents. He holds an AB in Physics from Harvard College and an MFA in Environmental Design from California Institute of the Arts. In 2012 he was the recipient of LBNL’s first “Lifetime Achievement Award for Societal Impact”; in 2014 received McGraw Hill/ENR’s prestigious “Award of Excellence” for “relentlessly working to reduce the carbon footprint of buildings and for moving the nation towards better building performance” and in 2016 was elected to the Facade Tectonics Institute College of Fellows.



Mic Patterson, Facade Tectonics Institute

Mic Patterson is a designer, researcher, educator, futurist, author, photographer and entrepreneur. He has concentrated his professional and academic career on advanced facade technology and sustainable building practices. He pioneered the introduction of structural glass facade technology in the United States in the 1990s, implementing diverse and novel applications including cable trusses, cable nets and grid shells. Patterson was among the founding group of the Advanced Technology Studio of Enclos, where he works as the Vice President of Strategic Development. He is a co-founder of the Facade Tectonics Institute and serves on the steering committee, and co-founder of the Facades+ conference series. He is on the technical research committee for GlassCon Global and a member of the Advisor Group for the Council for Tall Buildings and Urban Habitat. He has twice been named among the industry’s most influential by US Glass magazine. Patterson is a Ph.D. candidate in the School of Architecture at the University of Southern California with a research focus on sustainable facade renovation practices. He has taught, written extensively, and lectured internationally on diverse aspects of advanced facade technology. He is the author of Structural Glass Facades and Enclosures, published by Wiley.


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How to Cite

Boswell, K., Hoffman, S., Selkowitz, S., & Patterson, M. (2021). Skin Metrics: The Wicked Problem of Façade System Assessment. Journal of Facade Design and Engineering, 9(1), 131–146.